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Evolution of vertebrate eyes
A while back, I summarized a review of the evolution of eyes across the whole of the metazoa — it doesn't matter whether we're looking at flies or jellyfish or salmon or shrimp, when you get right down to the biochemistry and cell biology of photoreception, the common ancestry of the visual system is apparent. Vision evolved in the pre-Cambrian, and we have all inherited the same basic machinery — since then, we've mainly been elaborating, refining, and randomly varying the structures that add functionality to the eye.
Now there's a new and wonderfully comprehensive review of the evolution of eyes in one specific lineage, the vertebrates. The message is that, once again, all the heavy lifting, the evolution of a muscled eyeball with a lens and retinal circuitry, was accomplished early, between 550 and 500 million years ago. Most of what biology has been doing since is tweaking — significant tweaking, I'm sure, but the differences between a lamprey eye and our eyes are in the details, not the overall structure.
From those early pre-Cambrian days on, there have been two (well, three, but let's not get into that right now) basic kinds of photoreceptor: ciliary and rhabdomeric. The differences between the two are in cellular organization—rhabdomeric receptors have an apical elaboration of the cell membrane, while ciliary receptors modify a protrusion called the cilium to do the same thing—and in the cellular pathway they use to trigger changes in current flow across the membrane. Different lineages have appropriated these two kinds of photoreceptors in different ways. We vertebrates use ciliary photoreceptors in the image-forming part of our eyes; we have rhabdomeric receptors, too, but they're used in a more general way to sense light and dark, and play a role in circadian rhythms. Most invertebrates instead use rhabdomeric receptors for vision — the eye of the octopus, for instance, which superficially resembles ours, contains rhabdomeric photoreceptors instead of the ciliary rods and cones of our eyes. These ciliary receptors are found in all chordates, even in cephalochordates which lack true eyes, but do have simple light sensors.
The structure of ciliary photoreceptors at various stages of chordate/vertebrate evolution. The middle
row shows schematic diagrams of the entire photoreceptor; the top and bottom rows show electron micrographs of the
outer segment and the synaptic terminal, respectively. Note the gradual transition towards a highly organized laminar
structure in the outer segment and the appearance of ribbons in the synaptic terminal.
The proteins used in vertebrate photoreceptors are also ancient. The oldest distinction, between the proteins and pathways of rhabdomeric and ciliary receptors, can be traced back to pre-Cambrian animal ancestors, but later refinements, such as the evolution of separate rod and cone photoreceptors, occurred within the vertebrate line. The data suggest that cone opsins (the ones used for color vision) evolved and diversified first, and that the rods evolved later, as a specialized and novel kind of photoreceptor with greater sensitivity and dynamic range. The idea that black-and-white vision had to come first is a cultural artifact; the history of televisions does not repeat the history of vision. Lampreys are an interesting transitional form. They have a rod opsin, but it's intermediate in structure between the basal cone opsin and gnathostome rod opsin, and it's also found in receptors with a cone-like morphology.
The evolution of vertebrate opsins. On the left of the main figure is a dendrogram of the major opsin classes
that are relevant to the evolution of the vertebrate eye. Before the separation of protostomes and deuterostomes, the
primordial opsin had already diverged into three main classes: rhabdomeric opsins, which are characteristic of
protostome rhabdomeric photoreceptors (see upper photoreceptor schematic) but are also found in melanopsin-
containing vertebrate retinal ganglion cells; 'photoisomerase' opsins, such as retinal G-protein-coupled receptor (RGR)
opsin and peropsin, which may in fact be G-protein-coupled receptors; and ciliary opsins (see lower photoreceptor
schematic), which are characteristic of those photoreceptors in which the pigment-containing region is an expansion
of the membrane of a cilium. Vertebrate retinal opsins are represented by the lowermost six rows in the diagram. The
primordial retinal opsin of vertebrates diverged into long-wavelength sensitive (LWS) and short-wavelength-sensitive
(SWS) branches, and then the latter split into several sub-groups: SWS1, SWS2 and Rh2/RhB, each of which is
associated with cone-like photoreceptors. The Rh1 pigment of jawed vertebrates (bottom line) seems to represent the
most recent development among these classes, and is expressed in vertebrate rod photoreceptors. A separate class of
rod, the 'green rod' of non-mammalian vertebrates, uses the SWS2 pigment that is also present in the blue-sensitive
cones of these species. On the right of the main figure are presumed classes of G-protein coupling mechanism, residues
at four important locations (in the numbering system for bovine rhodopsin; blue and green shading highlights residue
similarity; pink shading highlights a chloride-binding site), and the regional expression of the opsins in vertebrate
tissues. AC, amacrine cell; GC, ganglion cell; HC, horizontal cell; RPE, retinal pigment epithelium; VA, vertebrate ancient.
An eye, to us, is much more than a patch of light sensitive cells, so while it's clear the molecular and cellular basis of photoreception is an old, old capability, there's the matter of building the elaborate light collecting structure of the eye, which is relatively more recent. How do vertebrates build an optical instrument of such sophistication? We can get the answer from development, and it also suggests an evolutionary explanation.
The diagram below summarizes the steps in vertebrate eye development, and do check out the flash animation of eye development.
Development of the vertebrate eye cup. a | The neural plate is the
starting point for the development of the vertebrate eye cup. b | The neural plate
folds upwards and inwards. c | The optic grooves evaginate. d | The lips of the
neural folds approach each other and the optic vesicles bulge outwards. e | After
the lips have sealed the neural tube is pinched off. At this stage the forebrain grows
upwards and the optic vesicles continue to balloon outwards: they contact the
surface ectoderm and induce the lens placode. f | The optic vesicle now invaginates,
so that the future retina is apposed to the future retinal pigment epithelium (RPE),
and the ventricular space that was between them disappears. Developing retinal
ganglion cells send axons out across the retinal surface. The surface ectoderm at
the lens placode begins to form the lens pit. This section is midline in the right eye,
through the choroid fissure, so only the upper region of the retina and the RPE are
visible. g | The eye cup grows circumferentially, eventually sealing over the
choroidal fissure and enclosing the axons of the optic nerve (as well as the hyaloid/
retinal vessels; not shown). The ectodermal tissue continues to differentiate and
eventually forms the lens. (There is an excellent animation of this illustration online.)
Vertebrate eyes are outpocketings of the brain. The neural tube bulges out two lateral bubbles of tissue that have the potential for light sensitivity; in the ancestral metazoan, this is probably all they had, paired patches of ciliary photoreceptors in the brain. Initially, light collection wouldn't have been a problem in a small, transparent organism, but as they grew larger and more opaque, there would have been selection for animals that had windows of transparency to allow light in to strike the photoreceptors. These could have been localized to just adjacent to the eyes by the acquisition of inductive interactions between the photoreceptive patch of the brain and the overlying epidermis; the eye spot instructs the skin over it to maintain transparency. Thickening of this transparent region into a lens would have gradually improved the image-forming capability of the patch, leading to the formation of the true vertebrate eye. The extended and folded over region of the brain would become the retina, retaining its connection to the rest of the brain through a thin stalk, the optic nerve.
This developmental process of progressive improvements in the structure of the eye reflects the evolutionary history of the eye cup as well. Each step in the process gradually adds more visual functionality, and exactly parallels the sequence of selective events hypothesized by Charles Darwin; every step adds a little more to the image-forming ability of the eye. The emerging functionality of the sequence is also apparent in the development of the lamprey, which carries it out with remarkable slowness. The larva of the lamprey, the ammocoete, is essentially blind, with light-sensitive cells that can do little more than discriminate between night and day. Over the course of about 5 years, it carries out the slow, steady construction of an eyeball with a differentiated retina, a lens, ocular muscles, etc., and then erupts onto the surface of the adult head as a recognizably full-featured vertebrate eye.
The structure of that retina is also important. It is more than just an array of photoreceptors—it's a complex image processing engine, with an array of repeating elements in addition to the photoreceptors that manipulates visual information before passing it on to the brain. Photoreceptors feed into bipolar cells that connect to ganglion cells, which are the actual neurons that send an axon back into the optic nerve. In addition, there are horizontal and amacrine cells that connect laterally, between the converging columns of receptor-bipolars-ganglion cells. The whole is a very precisely layered structure that again develops gradually.
The order of development of the retinal circuitry has some suggestive features that imply an evolutionary sequence.
The development of retinal neurons and circuitry. a | The cell cycle in the vertebrate retina. The soma of
a replicating cell migrates between the outer (ventricular) surface, where mitosis (M) occurs, and the inner (vitread)
surface. b | The sequential birth of cell classes in the vertebrate retina, with timings indicated for the ferret in both
post-natal weeks and caecal time (that is, the time relative to eye opening), which is probably a better comparator
for other species. c-e | The maturation of neural connectivity in the retina (again, timings are for the ferret).
c | Initially photoreceptors (which exhibit few adult morphological characteristics) send transient processes to the
inner plexiform layer (IPL), where they make synaptic contacts with the two sub-laminae. d | Subsequently these
processes retract, and developing bipolar cells insert themselves into the pathway between the photoreceptors and
the inner nuclear layer (INL). e | At a later stage, the rod and cone photoreceptors develop inner segments (IS) and
outer segments (OS). A, amacrine cell; B, bipolar cell; C, cone photoreceptor cell; G, ganglion cell; H, horizontal cell;
ILM, inner limiting membrane; OLM, outer limiting membrane; OPL, outer plexiform layer; R, rod photoreceptor cell.
In short, the ganglion cells, which connect to the brain, and the horizontal and amacrine cells, which form cross-connections within the retina, are the first cells to develop. The photoreceptors form next, but remember, the photoreceptors connect to the deeper elements of the retina through the bipolar cells…and the bipolar cells form last. This suggests that the bipolar cells are a relatively recent addition. Bipolar cells share morphological and gene expression similarities to the photoreceptors, which in turn suggests that they are modified photoreceptors themselves.
"Relatively recent addition," though, is still old. Lampreys have the same retinal circuitry and exhibit the same late-in-development addition of the bipolar cells, which means that the layered retina had to have evolved before the lamprey line split from the line that led to us — and that occurred about 500 million years ago.
This makes lampreys important as markers of an upper bound of the period of evolution of vertebrate image forming eyes. They've got all the major morphological characters of our eyes (and many deep differences as well—let's not get the impression that eye evolution stopped with the lamprey), and that means these features were assembled over 500 million years ago. What we need to do is look at species representing earlier splits from the vertebrate lineage to try and establish a lower bound…and interest focuses on the hagfish. What kind of eyes do hagfish have?
Hagfish turn out to have very poorly developed eyes that don't seem capable of forming an image at all. They are small conical masses buried beneath the skin, and they do not form a lens, they do not have extraocular muscles, they are barely a step up from a photosensitive eye patch. The retina has ganglion and photoreceptor cells, but no amacrine or bipolar cells. It's a very primitive structure.
Now comes the difficult part, though: interpretation. We can say the upper bound of the period of evolution of the eye is 500 million years ago, and where the lower bound falls depends very much on the phylogeny of hagfish, illustrated below.
The origin of vertebrates. The evolution of jawed vertebrates is illustrated against an approximate time-scale of
millions of years ago (Mya). The taxa considered in this Review are indicated with an asterisk and are accompanied by
schematics and diagrams of the 'eye' region. The earliest chordates, represented by extant cephalochordates and tunicates,
are thought to have appeared around 550 Mya. Jawless craniates (agnathans) were present in the early Cambrian, by 525 Mya,
and a time of 530 Mya has been indicated for their presumed first appearance. There is
considerable controversy as to whether myxiniformes (solely represented by extant hagfish) diverged before or after the
separation of lampreys from jawed vertebrates (shown as dashed black and grey lines). Numerous lines of jawless fish evolved
between 500 and 430 Mya ago, although none have survived to the present day. The first jawed vertebrate arose around 430
Mya, and this line is represented today by cartilagenous fish, bony fish and tetrapods. Six 'stages of interest' in vertebrate eye
evolution correspond to the time intervals between the divergence of important surviving taxa. This diagram does not
include the evolutionary changes that have occurred in the last 400 million years. The presented timeline is based primarily
on evidence from the fossil record.
(The mermaid to represent all gnathostomes, including fishes and tetrapods, is a cute touch, but let me assure you that this paper does not endorse the existence of mermaids or other mythical chimeras.)
One hypothesis for the evolution of hagfish is that they are a branch of the chordate lineage that split off approximately 530 million years ago, and are representative of the organization of the basal proto-vertebrate. That would tell us the the eye evolved after that branch point, placing all the major innovations in the morphology of the eye between 530 and 500 million years ago, within populations of lamprey-like ancestors. This is the hypothesis that Lamb and others prefer.
The alternative hypothesis is that hagfish aren't representative at all; they are degenerate forms that split from the lamprey lineage at some time after 500 million years ago. Their eyes are actually neotenous larval lamprey eyes, and don't tell us anything about the primitive state. What this would imply is that the lower bound of this window in time when the eye evolved is unknown; it could be pushed back to 550 million years ago, when the tunicate line split off…but they may have secondarily lost their eyes, too, which leaves that lower bound possibly dangling back a few more tens of millions of years.
The authors do make an argument that hagfish are plesiomorphic craniates that I won't get into. No matter which way the matter is settled, though, hagfish remain an important and interesting group to study in order to decipher the evolution of the eye, and working out the details of the differences between hagfish and lampreys are going to be central to understanding how our eyes arose.
Which brings me to mention two things I very much liked about this review: one is that it exemplifies good science, in that it makes clear, detailed predictions and proposes tests to evaluate those hypotheses. As listed below, these revolve around examining the relationships of tunicates, hagfish, and lampreys, and in identifying further shared and derived properties of the lamprey eye with other vertebrate eyes. This is the kind of specific checklist of ideas from which research scientists work.
Predictions and tests of our hypotheses of vertebrate eye evolution
Prediction 1: the phototransduction cascade components of tunicate ocelli should be homologous with those of hagfish
and lamprey photoreceptors.
Identify the G protein of Ciona intestinalis photoreceptors and compare it with those of hagfish, lampreys and jawed
vertebrates.
Determine whether other homologous cascade components (for example, phosphodiesterase and cyclic-nucleotide-
gated channels) are present in tunicate photoreceptors.
Determine the genomic organization of these cascade components and compare it with that of jawed vertebrates.
Prediction 2: at an early stage of eye evolution there was synaptic contact from ciliary photoreceptors onto rhabdomeric
photoreceptors.
Examine whether synaptic contacts occur between ciliary and rhabdomeric photoreceptors in extant protochordates,
such as Amphioxus and C. intestinalis.
Examine whether microvillar opsin-containing membranes are retained in the retinal projection neurons (ganglion cells)
of any extant organism.
Prediction 3: hagfish photoreceptors should exhibit close homology to cones.
Identify the ciliary opsin (or opsins) of hagfish and determine its (or their) phylogenetic relationship to other ciliary opsins.
Identify the principal phototransduction proteins (the G protein, the phosphodiesterase and the cyclic-nucleotide-gated
channels) in hagfish, and determine their phylogenetic relationship to vertebrate cone and rod isoforms.
Measure the electrical light responses and light adaptation of hagfish photoreceptors, and compare these with cone and
rod responses.
Prediction 4: the hagfish retina should not contain bipolar cells, and its photoreceptors should synapse directly onto the
projection neurons (ganglion cells).
Use retrograde labelling of hagfish ganglion cells to examine their synaptic inputs.
Use Golgi labelling of hagfish retina to investigate the connectivity of different cell classes.
Examine the synaptic contacts between cell classes at the ultrastructural level.
Prediction 5: if hagfish are monophyletic with lampreys, then they might represent a form with arrested development,
rather than a degenerate form.
Examine the phylogenetic relationship between cyclostome genes; in particular, examine the relationship between the
opsin genes to estimate the stage at which hagfish diverged.
Prediction 6: lampreys ought not to possess true rods.
Further characterize the photoreceptors of other extant species of lamprey to ascertain whether the morphological and
electrophysiological features of true rods are present.
Further characterize the opsins of lampreys, to ascertain whether the RhA/Rh1 pigment can be considered equivalent to
a rhodopsin.
Prediction 7: lampreys should not possess rod bipolar cells.
Carry out an immunohistochemical characterization of bipolar cell classes in the lamprey retina.
Carry out an electrophysiological characterization of lamprey bipolar cells.
Prediction 8: if vertebrate bipolar cells are descended from photoreceptors they will share numerous molecular
components or have very close homologues.
Compare the molecular components of cone and rod bipolar cells with those of cones and rods.
And another excellent feature of this paper is that it provides a detailed, step-by-step sequence for the evolution of the vertebrate eye. This isn't just a vague hypothesis, or a guess at unnamed, unspecified forces intervening at poorly understood points, but a description of known changes at the level of molecules, cells, morphology, and taxa. Here it is, a summary of eye evolution over 150 million years:
Proposed sequence of events involved in the evolution of the vertebrate eye
Stage 1: bilateral ancestor (>580 million years ago (Mya))
Animals with bilateral symmetry exist.
Numerous families of genes exist.
A range of G-protein-coupled signalling cascades exist.
A primordial opsin has evolved into three major classes: rhabdomeric
opsins, photoisomerase-like opsins and ciliary opsins.
A rhabdomeric-type photoreceptor has evolved, using a Gq-based
signalling cascade with a rhabdomeric opsin.
A ciliary-type photoreceptor has evolved, using a variant opsin (the
stem ciliary opsin) that probably coupled to a Go-based signalling
cascade.
~580 Mya
Protostomes separate from our line (deuterostomes).
Stage 2: protochordates (580-550 Mya)
The ciliary photoreceptor and ciliary opsin continue to evolve, becoming
similar to those in extant amphioxus and ascidian larvae.
A primordial RPE65-like isomerase evolves.
These protochordates had ciliary photoreceptors with a ciliary opsin and
a hyperpolarizing response, and were able to regenerate 11-cis retinal in
darkness.
Cephalochordates and tunicates separate from our line (chordates).
Stage 3: ancestral craniates (~550-530 Mya)
A ciliary photoreceptor evolves that has well organized outer-segment
membranes, an output synapse close to the soma and a synaptic
specialization appropriate for graded signal transmission.
Ciliary photoreceptors make synaptic contact onto projection neurons
that might have been descendants of rhabdomeric photoreceptors.
The eye-field region of the diencephalon bulges to form lateral 'eye
vesicles'.
These lateral vesicles invaginate, bringing the proto-retina into
apposition with the proto-retinal pigment epithelium.
A primordial lens placode develops, preventing pigmentation of the
overlying skin.
The resulting paired lateral photoreceptive organs would have
resembled the 'eyes' of extant hagfish, lacking any image-forming
apparatus and subserving non-visual functions.
Myxiniformes (hagfish) separate from our line (vertebrates).
Stage 4: lamprey-like ancestors (~530-500 Mya)
Photoreceptors develop cone-like features:
Highly-ordered sac/disc membranes evolve.
Mitochondria become concentrated within the ellipsoid region of
the inner segment1.
Coloured filter material is incorporated into the inner segment for
spectral tuning.
Ribbon synapses evolve in the synaptic terminal.
Genome duplications give rise to multiple copies of the
phototransduction genes.
Cell classes diverge to give five separate cone-like photoreceptors,
each with its own ciliary opsin and with isoforms of transduction
proteins.
Retinal computing power increases:
Cone bipolar cells evolve, either from proto-neurons or from
The bipolar cells insert into the pathway from photoreceptors to
ganglion cells, through the retraction of photoreceptor processes
and the incorporation of new contacts.
Bi-plexiform ganglion cells develop.
A highly organized three-layered neuronal structure with two
intervening plexiform layers develops.
Ganglion-cell axons project to the thalamus.
The optics evolve (the lens, accommodation and eye movement):
The lens placode invaginates and develops to form a lens.
The iris develops and a degree of pupillary constriction becomes
Innervated extra-ocular muscles evolve.
The resulting eye and visual system would have resembled that in extant
lampreys and would have provided spatial vision at photopic intensities
and over a broad wavelength range.
Petromyzoniformes (lampreys) separate from our line.
Stage 5: jawless fish (~500-430 Mya)
Myelin evolves and is incorporated throughout the nervous system.
Rod photoreceptors evolve:
Rhodopsin evolves from cone opsin.
Rod isoforms of most transduction cascade proteins arise.
Free-floating discs pinch off within the plasma membrane.
Rod bipolar cells evolve, possibly from rod photoreceptors.
The scotopic rod pathway evolves, with a new subset of amacrine cells
(AII) providing input into the pre-existing cone pathway.
A highly contractile iris evolves that can adjust light levels.
Intrinsic eye muscles develop that permit accommodation of the lens.
This eye possessed a duplex retina that contained both rods and
cones, together with retinal wiring that closely resembled that of
jawed vertebrates, with colour-coded photopic pathways and a
dedicated scotopic pathway; it was probably similar to that found in
many extant fish.
The last jawless fish separate from our own line (gnathostomes).
Stage 6: gnathostomes (<430 Mya).
In the case of tetrapods:
The lens develops an elliptical shape to compensate for the added
refractive power that is provided by the cornea in air.
The dermal component of the split cornea is lost and the eyelids
evolve.
Certain opsin classes are lost, for example, SWS2 and Rh2 in
mammals, under extended nocturnal conditions.
That's a beautiful illustration of the power of theory: it creates a framework of observations in which to work, and is going to help us place new observations and experiments (and there will always be new discoveries) in a context. I'll be filing this away and using is a reference in further reading about eye evolution.
Lamb TD, Collin SP, Pugh EN Jr. (2007) Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup.
Nat Rev Neurosci 8(12):960-76.
Development, Evolution, Science
…now what is the probability of all that happening?
Braxton Thomason says
The probability is 1 — it already happened :P
Glen Davidson says
Yeah, but couldn't it all just be chance that eyes and everything else appears to be evolved? I mean, the tree of vertebrate life could just be a random happenstance, or the designer's skills could somehow be exactly the same as evolution's is.
Well, that is basically the argument from "the other side."
Glen D
http://tinyurl.com/2kxyc7
Blake Stacey says
Wow. . . just. . . wow.
Brownian, OM says
What I wanna know is when did the Abrahamic eye, which allows one to see the obvious hand of God in everything, develop snd split off from the eye of the rest of humanity, which variously sees gods, spirits, demons, monsters, chimeras, or nothing at all?
remy says
NAAAAAHHH,
What's more likely? All that complicated "evolving" stuff or someone with really big thoughts thinking, I think I'll make eyes? I mean sheesh, you scientists.
PZ Myers says
Must have been about the time we evolved a bicameral mind. Or when nomads discovered psilocybin.
TomS says
The image for the typical jawed vertebrate – are my eyes fooling me, or is that a merman?
Tony Popple says
PZ said: "The mermaid to represent all gnathostomes, including fishes and tetrapods, is a cute touch, but let me assure you that this paper does not endorse the existence of mermaids or other mythical chimeras."
Yet another example of the evil Darwinist plot to remove "alternative" theories from science.
I love these types of posts. They are just the right length and level of language to digest.
Come on, folks, don't you realize that Behe and Dembski et al. have proved (proved, I say, proved!) that the eye would be impossible unless goddidit?
Sven DimIlo says
Waitaminute…why are there still hagfish?
Tom said "Come on, folks, don't you realize that Behe and Dembski et al. have proved (proved, I say, proved!) that the eye would be impossible unless goddidit?"
So, the question isn't if god did it. Rather, how drunk was he at the time?
tintenfisch says
We know from the bible that God created man in his own image. Therefore the eye is a divine structure. The real question is, why would God go through so much trouble to design a less complicated and more "primitive" eye in hagfish and lamprey?
It just doesn't make any sense.
RJM says
Brownian, OM said: "What I wanna know is when did the Abrahamic eye, which allows one to see the obvious hand of God in everything, develop snd split off from the eye of the rest of humanity, which variously sees gods, spirits, demons, monsters, chimeras, or nothing at all?"
It's more likely that the truth-seeking eye evolved from the Abrahamic (or "truth"-seeing eye) during the scientific revolution, and has continued to be refined since. Unfortunately, natural selection was subverted by politics, so the more evolved form has yet to establish itself in the majority of Sapiens.
I have a prediction about how the creationists will interpret this.
Because the major morphological features of the vertebrate eye have an origin sometime before 500 million years ago, what they will see is "Poof! The eye appeared fully formed in the Cambrian!" and they will call it evidence of a designer. They will ignore the multiple steps documented here, and the fact that vertebrate eyes have diverged in different directions and with different refinements since.
Anyone want to take the bet?
capitalistimperialistpig says
So do the jellyfish eyes share a common ancestry with those discussed in detail here?
Except that they'll also demand to see every step in the evolution of each eye that has evolved. You know, to be fair, since science is utterly incapable of extrapolation or of inference when any step is missing.
since science is utterly incapable of extrapolation or of inference when any step is missing.
I forgot to add that it changes again when every step is missing, as with ID. Then it becomes science.
This looks to be a serious setback for evolution
1st figure above, bottom row, second from right EM image:
The lamprey retina is clearly giving us the one-fingered salute!!!
Only an intelligent designer could have done that. A crafty intelligent designer, one with a sense of humor, but an intelligent designer nonetheless.
No, I like the bicameral mind hypothesis.
Explains Dubya's decisions perfectly.
I suppose it means that, in atheists, the unassailable god-part of the brain is stuck in endless filibustering, leaving the bureaucratic man-part to reason its way through life.
Sounds like Canadian politics, but less boring.
Ow! My mind just had a vote of non-confidence.
Evolution of mousetrap:
http://community.livejournal.com/lolscience/15129.html
[btw, Behe dolt, a designed mousetrap is configured very differently from an evolved one. How can you be so stoopid?]
MAJeff says
This is way cool.
I was on the phone with a friend yesterday. She knows I'm an atheist, and she was going on about something. I mentioned what I thought, how amazingly complex we are and how neat it is that evolution developed us of all things, and she just went off about going to church and believing and how that doesn't make her a bad person blah blah blah. It's amazing how touchy people get. Even saying that shit like this is amazing becomes somehow an attack, because it doesn't explicitly acknowledge "something bigger" or "meaning."
Who cares? this shit's cool in and of itself.
Schmeer says
…this paper does not endorse the existence of mermaids…
Blasphemy! I will not suffer such an attack on my faith.
C'mon man! You believe in pirates and octopuses, how can you stop short of the mermen! Triton will get you with his big pointy trident of doom.
Paul Burnett says
Brownian OM wrote (#20): "I like the bicameral mind hypothesis."
That actually makes sense: Creationists still hear voices in their heads, and evolutionists have evolved beyond that.
Looks like I either mislinked, or something's wrong with the system. Here's the "Question" link that didn't make it in my post above:
Just testing to see if it links
In order for your evolutionary view to prevail, you must somehow demonstrate that evolution has the power vested in it by you and you must demonstrate that random, non-directed processes such as mutation have the power to organize and assemble highly integrated systems in which means are adapted to ends.
Since there's no evidence of any direction, the fact that that's indeed how it happened is obviously evidence that non-directed rocesses such as mutation have the power.
But then again, Christianity was a pretty good story too, and it's lasted over 2000 years. I guess truthfulness is not a necessary requirement for longevity in the fairy tale business.
Hinduism's even better (and older) than your silly fairy tail.
Plus, it involves fewer unicorns, which are, quite plainly, mythical.
hmmmmm this "gypsy biker" guy sounds reeeeeal familiar…it was a thread just a day or two ago…in fact I think he actually used the eye example all by hisself…
aaaa hell I can't find it.
He's a definite sockpuppet though.
I wrote the following parody of the IDiots, which nevertheless is about the same as the nonsense that gypsybiker later spouts:
Congrats, gypsybiker, you basically managed to make the same stupid argument that I brought up, showing that you neither know science nor how to read competently.
Why can't any of you anti-evolutionist dolts understand the importance of prediction in science? The thing is, tard, that the predictions of non-teleological evolution have been fulfilled, and you morons neither understand the importance of that, nor do you have any kind of theory or hypothesis that explains what evolutionary theory explains.
Now if you still don't understand, bug off and take some high school courses to replace the idiocy filling your brain with some actual knowledge of science.
uh…wrong thread? D'oh!
Eamon Knight says
The mermaid to represent all gnathostomes, including fishes and tetrapods, is a cute touch….
Consider it a "representative generic morphology". You vertebrates are such a minor group, no one can be bothered keeping all your trivial anatomical variants straight!
The "gypsybiker" twit is the banned and spectacularly obnoxious Charlie Wagner. I clean up his messes as quickly as I encounter them.
phew! I mean, I know I need sleep real bad (freakin lab reports!!!!), but that kind of scared me for a second.
Wagner, of course…reeeeeeally reeeeeally familiar.
How come so many of the religious posters (who are only concerned with the truth) need to set up so many sock-puppets to hide who they are?
If you believe what you say, then say it and use your own name or, at the very least, a consistent alias. C'mon now, St. Sebastian took a hundred arrows for his faith, surely you can post on a blog without resorting to a coward's tactics in defence of yours.
Whatsa matter? Afraid that God doesn't really have your back?
jbp says
Beautiful synopsis of the paper, PZ. It was this very thing–the evo-devo majesty of the eye that inspired me to become a research biologist lo these many years ago. Reading your lovely review today transported me back to the moment at which I realized that to make a career of studying such elegant intricacies would be the most phenomenal, fulfilling vocation on earth.
I feel really sorry for the millions of stunted, blinded sheeple who cannot–WILL not appreciate how beautiful the natural world is all on its own–who can only marvel vaguely about what a wonderful 'designer' must have dunnit.
In what way does realizing the full extent of these magnificent developmental/genetic refinements over hundreds of millions of years NOT kick 'godditit"s ass??
All this evidence indicating variations on a theme gradually leading to more complex and generally better functioning eyes just screams out design, doesn't it? ;)
Mark (Monty) Montague says
I'd love to see the same sort of thing applied to the protostomes and showing the basal aspects of the opsins and how they support convergent evolution and compare-and-contrast, but even more, I'd like to see a similar assessment go back further to the origins of opsins and such, and how photopigments are related in euglena phototaxis, photosensitivity and photosynthesis in much earlier or disparate organisms. The history of opsins and pax6 seem like a great thing to take as far back as we can to the origins… clearly, trilobites had rather sophisticated lens structures so they presumably had similarly sophisticated retinal and neural mechanisms as well. I know a lot of animals have extraocular photoreceptors and plants and certainly eukaryotes and possibly prokaryotes have phototaxis of various sorts, and knowing how those are interrelated would be great… I've heard opsins are believed to have an origin in some sort of unicellular photosynthesis.
On a related note, people who know this stuff should probably make some effort to fix the stupidities at http://en.wikipedia.org/wiki/Evolution_of_the_eye — I hoped mentioning the stupidity of saying a "unicellular invertebrate euglena" has an "eyepatch of photosensitive cells" in the talk page would prompt someone who knows euglena to fix things properly, but so far, it's festered in stupidity for a year or so. Of course, I predict that merely mentioning that page here will lead to it becoming a skirmish in rabid creation/evolution madness, but it's pretty awful mess already… even in sections where I agree with the points, the details about cephalopod and stomatopod eyes are a bit muddled or poorly phrased.
@36 my eyes suck
I'd be long dead if I was a hunter gatherer type
@#38, My husband the optometrist's pet (albeit wild-assed) theory is that myopes stayed in the gene pool because of their value as cave painters and fine motor skill workers. Diligent labor of this sort bought them a share of the hunted and the gathered.
However, this would only be a workable system if the myope in question had sufficient intelligence to perform these tasks. Stupid myopes would presumably not make the cut. Hence my husband's (who, btw, is a raging myope himself) totally unscientific addendum to this theory is a positive correlation between myopia and intelligence.
Ichthyic says
Because the major morphological features of the vertebrate eye have an origin sometime before 500 million years ago, what they will see is "Poof! The eye appeared fully formed in the Cambrian!"
well, PZ, I'm sure they will quotemine this part of your original post:
Most of what biology has been doing since is tweaking
and say:
"See, even evilutionists say it's all just microevolution – I mean, it's still just an eye!"
taking bets on what the stupid and dishonest will do isn't entertainment, it's so predictable it's boring.
you'd have to lay huge odds to make that bet even remotely interesting.
say, 20 to 1, maybe?
Divalent says
PZ: "The data suggest that cone opsins (the ones used for color vision) evolved and diversified first, and that the rods evolved later, … The idea that black-and-white vision had to come first is a cultural artifact; the history of televisions does not repeat the history of vision. "
This cannot be correct: to "see" in color requires two or more sets of photoreceptors sensitive to different wavelengths. Presumably one evolved first before a duplication event produced a second pigment that could evolve a different sensitivity. Until you have more than one, it's a black-and-white world.
PZ, I think he has a crush with his "For your eyes only" notes.
David Marjanović, OM says
One hypothesis for the evolution of hagfish is that they are a branch of the chordate lineage that split off approximately 530 million years ago, and are representative of the organization of the basal proto-vertebrate. That would tell us the the eye evolved after that branch point, placing all the major innovations in the morphology of the eye between 530 and 500 million years ago, within populations of lamprey-like ancestors.
At face value, yes, but don't all hagfish live rather deep in the sea, where eyes aren't much good? In other words, are hagfish from a purely ecological perspective expected to have vertebrate eyes? If not, their eye patches cannot be taken as evidence of anything other than their (present) habitat.
cue Sheena Easton and the naked, gun-toting silhouetted Bond-girls…
Ah, but the point is that the duplication and divergence of cone opsins came first, and the key distinction about cone opsins is that they have more wavelength specificity and don't saturate at higher levels of illumination. It's true that with one opsin, you can't have color vision, but color vision was easy to acquire.
Familiarize yourself with the caecilian tentacle. The muscles that move it are slightly misplaced eye-moving muscles, the gland that lubricates it is the slightly misplaced Harderian gland that lubricates the eyeball in other land-living vertebrates… yet it's an appendage that's used for some kind of smelling.
jbp, where did you get that association…?
I'll reprise PZ's earlier post as an explanation (also for my immediate previous post):
he was here again insisting that his posts were really for PZ's eyes. He's got an admirer
yet it's an appendage that's used for some kind of smelling.
yeah, yeah, so you can smell with your eye(stalk).
still just an eye.
seriously, I can't lose this argument, so long as i keep saying:
"it's still just an eye"
which, of course, is the point.
you simply can't argue with the utterly inane.
which is also why I would want huge odds in my favor before I would consider taking up PZ on his bet.
i have to say that it's a sad testament to the current day that you felt you had to include the disclaimer about the mermaid…
otherwise, I love this sort of post. I feel so much better after learning something new (to me) like this. makes my whole day. thanks very much.
but don't all hagfish live rather deep in the sea
not all, no. Moreover, I'm not conversant with hagfish paleontology, but I'd still bet that the fossil record would show they haven't always been most prominent in the deep benthic zone, either.
as a side note, even the common hagfish is under tremendous fishing pressure at the moment, and the feds are actually considering stricter fishing regulations on it.
http://www.fish-news.com/cfn/editorial/archive/CFN_6_07_archive.html
ever seen a hagfish in action? they are perhaps the most prolific "slime factories" on the planet. just one can turn a 5 gallon bucket into a solid mass of slime in just a few minutes. Don't get me started on some of their other disgusting habits. It's definetly one of those: "So disgusting, it's fascinating" type of critters.
It's hard to imagine there is a big fishery for it, except in the context of the fact that so many other fisheries have been so heavily overfished over the last few decades.
… In fact, it seems that the market for hagfish is related to the Asian trade in "aphrodisiacs".
(pardon the reference to fox news):
http://www.foxnews.com/story/0,2933,285079,00.html?sPage=fnc.scitech/naturalscience
someday, I've got to put together a list of all things that are typically considered "aphrodisiacs" in the more "wooish" parts of Asian culture.
gotta be in the thousands, at least.
Bride of Shrek, FCD says
Now, now, we all know the eye is far too complex to have evolved by any other means than through the hand of god. Even Charles Darwin said so
http://darwin.gruts.com/misc/faq/eye-complexity/
ngong says
#53…I was surprised to see a hagfish tank at an aquarium in Bangkok a couple months ago. No slime at all, though the placard mentioned their slime-producing talents. What's going on there?
Ichhtyic says
hagfish only produce the proteins that cause massive "slimation" when they are stressed.
it's an anti-predatory response.
Field Notes says
Very interesting. That sounds exactly like the kind of book/article I'd enjoy reading.
I would have never guessed the cones evolved before rods.
I also wonder – The stages of retinal cell development – is that information theoretical? If born out in an observational study, how'd they do it?
I'm going to have to track down the original – this subject is way too interesting to just be satisfied with a blog post =D
thalarctos says
I was surprised to see a hagfish tank at an aquarium in Bangkok a couple months ago. No slime at all, though the placard mentioned their slime-producing talents. What's going on there?
You must not have made them angry. Ichthyic's reference is to their behavior when forcibly caught, so naturally they're pretty motivated in that situation. Lounging around their home tank, on the other hand, without a specific threat would mean not so much reason to go into self-defense mode.
By "aquarium", do you mean an educational exhibit or a tank where they were waiting to be sold? I have heard they are eaten in the Philippines, for example. But keeping them alive and well and happy in captivity for an extended period (as opposed to just to market) is very difficult, I understand.
My vert embryo class was in 2004, so this info is somewhat dated, but I haven't heard of this particular nut being cracked yet: my teacher (PZ: hi from Billie!) told us that the difficulties of raising hagfish in captivity meant that we didn't have a comprehensive account of hagfish development, and that any of us who went on to solve that particular problem would become famous pretty fast.
@#38
Epigenetics. How about that as an explanation for myopia?
nn says
Apparently the hagfish slime is a quite interesting substance.
It has also recently been discovered that the mucus excreted by the hagfish is unique in that it includes strong, threadlike fibres similar to spider silk. What is interesting about hagfish slime is that it is fibre-reinforced. No other slime secretion known is reinforced with fibres in the way Hagfish slime is. The fibres are about as fine as spider silk (averaging two micrometres), but can be twelve centimetres long. When the coiled fibres leave the Hagfishes' 'slime' gland, they unravel quickly to their full length without tangling. Research continues into potential uses for this or a similar synthetic gel or of the included fibres. Some possibilities include new biodegradable polymers, space-filling gels, and as a means of stopping blood flow in accident victims and surgery patients.[/quote]
as a means of stopping blood flow in accident victims and surgery patients
Heh–I can see it now: "Hagfish–when leeches just aren't disgusting enough."
(I know; they're opposites. Leeches anti-coagulate; apparently, hagfish coagulate.)
Seriously, nn, that's very cool.
That video about hagfish slime is also pretty cool.
http://www.videosift.com/video/High-power-slime-from-the-hagfish-one-of-natures-miracles
David (@#47), I was responding to MAJeff's comment on the troll du jour's response to PZ–to paraphrase (the troll): "Fiddle-dee-dee, it doesn't bother me when you delete my posts, dearest, because I know that you have at least had to read them to do so, and they are for your eyes only". This brought to mind the Bond movie/theme song of that name. Comically enough, your cerebral hagfish post hit the board just seconds before my throwaway pop-culture reference. Quite the non-sequitor.
I'm now highly entertained by the image of naked silhouetted Bond girls swimming gracelessly through copious clots of hagfish slime :)
Oh, and Field Notes, (re: #56) The sequence of retinal development is fairly straightforward to observe with the right cell-specific markers, either in staged, fixed eyes with antibodies/RNA probes or in live embryos with GFP hooked up to some cell specific promoter. The position, as well as the morphology, of retinal cells is stereotypical and easy to interpret, and expression of cell-specific genes lets you know when the cell is specialized enough to turn these genes on, hence a 'birth order' can be elucidated reproducibly. There are a number of pretty zebrafish papers on this very topic, if you're interested.
And epigenetics? We can trot that out for just about any trait, really. There have been some studies indicating epigenetic effects on myopia, but the methodology was fairly poor in the ones I'm familiar with.
#55…that makes sense.
#57…It's "Siam Ocean World"…a surprisingly classy complex under a Bangkok shopping mall.
The rule around here is that you can eat it if it won't kill you, but I've yet to hear of tom yum hagfish. So they're probably not caught in abundance in the Andamans or Gulf of Thailand.
hexag1 says
With all this in mind, what is the general consensus on Andrew Parker's view that the Cambrian explosion was triggered by the sudden evolution of vision in primitive trilobytes?? This is the theory explored in his book "In the Blink of an Eye"
John Phillips, FCD says
Thanks for an extremely interesting and fascinating post PZ. I have lost count of the number of times I have had the complexity of the eye as reason for a designer thrown at me in 'discussions' with cretinists and IDiots. Unfortunately, no amount of evidence will ever convince the blindly ignorant cretinist or IDiot.
Stuart Dryer says
All vertebrates from lampreys on have a medial eye (the pineal organ/gland/complex) as well as two lateral eyes. Lampreys and most other anamniotes have fairly complex organization in the pineal; there are ciliated photoreceptors with nicely developed outer segments, opsins, cGMP-mediated phototransduction cascades, ganglion cells, interneurons, etc. There are also more endocrine-like pinealocytes that are also light sensitive ciliated photoreceptors that resemble the pinealocytes that persist in amniotes. In lampreys, pineal ganglion cells project to the tectum and other visual centers.
However, hagfish and amphioxus are generally said to lack this medial eye.
I have not given this much detailed thought but I wonder if this has implications for understanding the evolutionary questions nicely outlined in this post. Of course it is possible that the situation in hagfish represents ontogenetic loss of all visual structures that affects medial eyes more severely, but I also read in a quick search that no pineal anlage has every been found in hagfish.
nbm says
OK, Monty, your 'mentioning the stupidity of saying a "unicellular invertebrate euglena" has an "eyepatch of photosensitive cells" in the talk page' at Wikipedia stayed there unnoticed for more than a year. I'm sure I know less science than you do, but I trod where angels like you fear to and 'fixed' it. I simply decided that 'eyespot' should refer to photosensitive protein and 'eyepatches' are multicellular. Now will someone who knows a lot more please go and fix my fix? Thanks.
Jim Thomerson says
Have you noticed that, in none of the fictional stories about invisible men, does the author realize that the invisible man would be blind?
Thanks nbm! It certainly seems better to me… of course, the whole page has quite a few weird claims; I'm not exactly sure what the heck they're going on about in the '"Backward" Illumination of the Retina' business, either… I think they're trying to say that the vertebrate retina is inside-out (light has to pass through layers of neurons and blood vessels and such) while the cephalopod retina isn't… but I don't know of any case where one "flips" relative to the other… their development is quite different… IIRC, the vertebrate one is an extension of the brain, while the cephalopod one develops as a pit in some outer structure like the skin.
Keith Douglas says
mmmhypothetico-deductive-y.
Dr. Steve Thomas says
Do you guys actually believe what you are writing?
"Cone bipolar cells evolve. Ganglion-cell axons project to the thalamus. (How the hell did they know where to go?) Myelin evolves and is incorporated throughout the nervous system. Intrinsic eye muscles develop that permit accommodation of the lens. A highly contractile iris evolves that can adjust light levels. The dermal component of the split cornea is lost and the eyelids evolve." Just like that. They evolve like they know EXACTLY where they are going.
And because the eye is here and make-believe steps are listed, that means it happened THAT WAY? (The probability is 1 — it already happened :P-Thomas Braxton 2nd comment) Is this magic? Were these events happening in millions of animals all at the same time? All of these remarkable and astronomically unlikely mutations, and their selection by NS, all happening exactly the same way in thousands of specie populations in unison? Do you think that by listing the steps, and making the steps sound scientific, that makes it believable? If we could go back 525 MYA, would we see millions of species with hemi-ping pong ball eyes? I really doubt it.
You must think that by adding a scientific looking cartoon, the the worshipers will believe even more. They probably will. The miracle of evolution is that people with highly intelligent minds believe it without even questioning or wondering, just like the miracle of religion. What really amazes me is that people that believe this unbelievable stuff make fun of those that don't. Like me.
Owlmirror says
They evolve like they know EXACTLY where they are going.
They don't "know" where to go. The traits arose as minor mutations; since each mutation allowed the possessor of the trait to survive better, the bearer of the trait left more offspring. The success of those offspring spread the trait through additional generations.
Were these events happening in millions of animals all at the same time? All of these remarkable and astronomically unlikely mutations, and their selection by NS, all happening exactly the same way in thousands of specie populations in unison?
If you pay attention, you will note that the whole point is that the trait slowly spreads through a population that can interbreed; through the same species. If the population with the trait can no longer interbreed with a population that doesn't have the trait, then the two populations can then evolve into new species.
Do you think that by listing the steps, and making the steps sound scientific, that makes it believable?
The steps that are listed are from the evidence; from actually examining eye development in many different species. Examining and describing the evidence are indeed part of science.
What really amazes me is that people that believe this unbelievable stuff make fun of those that don't. Like me.
Since the entire modus operandi of evolution-deniers is to make fun — that is, to demonstrate ignorance and confusion by attacking a strawman version of what evolution is — then why do you deserve more than being made fun of in return?
truth machine says
What really amazes me is that people that believe this unbelievable stuff make fun of those that don't.
I can't think of any good reason not to make fun of someone as pig-headedly stupid, ignorant, and arrogant as yourself.
The miracle of evolution is that people with highly intelligent minds believe it without even questioning or wondering
Excuse me, dumbfuck, but what evidence do you have of that? Just because people who aren't as retarded as you are have reached a different conclusion than you have doesn't mean that they didn't deliberate.
stevebee92653 says
O: They don't "know" where to go. The traits arose as minor mutations; since each mutation allowed the possessor of the trait to survive better, the bearer of the trait left more offspring. The success of those offspring spread the trait through additional generations.
S: So a few eye cells that "evolved" would trump speed, size, and aggressiveness? And the individuals that evolved those few eye cells would triumph? Right. There are so many traits that result in survivability, why would a 1% eye be better than bigger claws or more speed and strength?
O: If you pay attention, you will note that the whole point is that the trait slowly spreads through a population that can interbreed; through the same species. If the population with the trait can no longer interbreed with a population that doesn't have the trait, then the two populations can then evolve into new species.
S: So the population with the trait (eyes in this instance) spread them to other species by, uh, hmm. Since one specie can't procreate with another, the eyes would be stuck in one specie, if it was possible for that evolution to happen in the first place. It would be unthinkable for nearly identical mutations that produce eyes to occur in thousands of species at the same time. So evolution is really stuck.
If you went 500 MYA, do you think you would see some in an animal population with half "ping-pong ball" eyes, some without eyes, and some with fully evolved eyes?
O:The steps that are listed are from the evidence; from actually examining eye development in many different species. Examining and describing the evidence are indeed part of science.
S: Many different CURRENT species have been examined. There is no evidence of fossils that show evolution of the eyes. It should be pretty obvious with fossil skull structures. They should show enlarging eye sockets. They don't.
O: Since the entire modus operandi of evolution-deniers is to make fun — that is, to demonstrate ignorance and confusion by attacking a strawman version of what evolution is — then why do you deserve more than being made fun of in return?
S: "Strawman": right out of the pro-evolution arguers handbook in the chapter on "When You Can't Answer"! Good going! Also don't forget to use "ad homonym attack" when there is no reasonable answer.
O: I can't think of any good reason not to make fun of someone as pig-headedly stupid, ignorant, and arrogant as yourself.
S: Again, right out of the handbook: "Call them names if you can't come up with a reasonable answer. Use stupid, ignorant, retarded, arrogant, and mix in as many four letter words as you know!" p. 38
O: Excuse me, dumbfuck, (right on!) but what evidence do you have of that? Just because people who aren't as retarded as you are have reached a different conclusion than you have doesn't mean that they didn't deliberate.
S: Thanks for the compliment! Evolutionists come up with impossible explanations, then, as you say, "deliberate" on them, then all agree they are not impossible, then go forward in lock step with articles and books.
Evolutionists come up with impossible explanations, then, as you say, "deliberate" on them, then all agree they are not impossible, then go forward in lock step with articles and books.
Cretin.
Michael X says
why would a 1% eye be better than bigger claws or more speed and strength
Wow, where to begin? You ever fought an equally matched fighter with your eyes closed? I recommend it, just for you.
You think photon receptive cells developed after claws? Not to mention that the very ideas of "speed" and "strength" are commonly involved with complex evolved musculature. Tack on the very audacity to reject evolution simply because you're too ignorant or lazy to try and find out why being able to sense light levels could pay off more than "speed," "strength," or any other vague adjective, and we're left with nothing more than a testament to your mind set.
What makes evolutionary biologists different from nonsense peddling charlatans such as yourself (and I mean that in the most pejorative way, just so you don't get me wrong.) is that when we come up against something unexpected, or even nominally interesting, we attempt to figure it out. You on the other hand declare every unknown a victory for your ignorance and shamelessly revel in it. It's almost like you've never read a history book. It's filled with cocky know-nothings just like you who later are shown up by steadfast scientists.
Read up before coming back kiddo. You're embarrassing yourself.
Not that we don't mind laughing…
They evolve like they know EXACTLY where they are going
Dr, I think perhaps you're not familiar with the theory of evolution?
You see this is my classy, "framed" question. I hope to prove a hypothesis among some friends of mine as to how you'll react, when after having made this statement, I ask you where you get you information on evolutionary theory? And more to the point, how you've come to the conclusion that that information overrules an entire scientific endeavor?
I will expect a clear, reasonable answer if we are to take the title 'Dr." seriously. Otherwise, you will be perfectly subject to all the mocking this group of posters can produce. Which I promise is a great deal. I expect great things.
And thus ends my measured response.
They should show enlarging eye sockets
Should the evolutionary history of "skulls" show enlarging eye sockets? Where did you come up with that? I really want to know. I'm wondering where you've gotten your info on evolution. As an after thought I suppose I could ask you to support the claim that such evidence is lacking. You, being so questioning of assertions, will of course be perfectly understanding and willing to provide, so as to not look hypocritical, a reference. I'd love to know where you read or heard such a claim, so as to read it myself.
Never to late to start learning. Yeah?
I'd also love to read this "pro-evolution arguers handbook." Can I get it on amazon? I'd hate to make any mistakes you've pointed out so far. Otherwise, by not being level headed and reasonable, someone could refute my arguments, not on their merit, but on the fact that someone was less than decorous. Heaven forbid, yes?
O: You ever fought an equally matched fighter with your eyes closed? I recommend it, just for you.
S: Your problem here is "equally matched". You must know that no two animals or species in nature are "equally matched". Do you think a fighter who weighs is 5′ 7″ and 130 lbs.with a pair of 2% evolved eyes could defeat a blind Mike Tyson? Gimme Mike every time.
O: What makes evolutionary biologists different from nonsense peddling charlatans such as yourself (and I mean that in the most pejorative way, just so you don't get me wrong.) (THANKS!) is that when we come up against something unexpected, or even nominally interesting, we attempt to figure it out.
S: Then why don't you "figure it out" instead of calling me names if you are such a goddam "steadfast scientists"? The most amazing name you have called me is arrogant, since 80% of your writing involves demeaning me. You have constantly skirted my very reasonable question of:
QUESTION: Did eyes initially evolve in only one specie or were these astronomically unlikely events happening in millions of animals/species all at the same time? If in one specie, eyes could not have spread to other species. And the concept of millions of specie populations all undergoing the exact same mutations at the same time that would lead to vision is not even thinkable.
Can you "figure it out"?
Oops. Claws came after "light sensitive cells". Whatta goof. You caught me. OK, limbs; strength; speed; aggressiveness; health. I think you get the idea.
And let's not get into a debate on who is the most schooled in biology and evolution. You would probably lose. So go ahead and laugh all you want. Talk like that only makes you look juvenile. For many years I argued on the side of evolution. But I never demeaned my opponent like you demean me. I am certain you act the same with anyone who has a reasonable question about your "science". In my case too many questions started coming up about evolution; too many impossibilities. Like the question that I posed for you. When I was an evolution believer, I couldn't answer it, just like you can't. The same question arises with every organ and biological electro-mechanical system. Try answering that question for the heart-lung system, the musculo-skeletel system. I am positive that your only answer will be to demean the asker.
My recommendation to you and all other evolutionists is to calmly and intelligently answer reasonable challenges. If evolution is real science, you should be able to do that. That way you may get some doubters who will change their minds about the science that you so deeply love and are so dedicated to.
Stanton says
Stevebee92653: you do not sound like you were ever an "evolution believer," you sound like someone who did not bother to understand how evolutionary biology works in the first place. If you understood how evolutionary biology works and is defined, you wouldn't make deliberately childish demands of
"Did eyes initially evolve in only one specie or were these astronomically unlikely events happening in millions of animals/species all at the same time? If in one specie, eyes could not have spread to other species. And the concept of millions of specie populations all undergoing the exact same mutations at the same time that would lead to vision is not even thinkable.
Among other things, fossils of the earliest recognized chordate, Haikouella, from 525 million years ago, show that chordates developed primitive, very simple eyes very early in their history.
The first vertebrates appeared 500 million years ago, and they, including Arandaspis, Sacabambaspis and Astraspis had eyes much larger than Haikouella, but were still less complex than the eyes of later vertebrates, such as Thelodus or Cephalaspis, and were much smaller (as well as simpler) than the eyes of primitive gnathostomes ("jawed vertebrates"), such as placoderms like Coccosteus.
Stevebee92653, if you want people to take you and your viewpoints seriously, first, please lose the unpleasant and aggressive attitude: it gives people a poor estimate of your social skills, and suggests (hopefully wrong) that you are nothing more than an anti-intellectual troll who picks fights for Jesus. Second, please try to actually learn about vertebrate evolution before you go about "questioning" evolutionary biology. I recommend reading "Discovering Fossil Fishes" by John Maisely. It is a very well written book with excellent, informative pictures (it could stand to have had more pictures, but, I'm not in charge of that).
http://www.amazon.com/Discovering-Fossil-Fishes-Henry-Reference/dp/0805043667
Among other things, fossil evidence currently suggests that eyes developed once in chordate evolution, and evidence from genomic sequencing is still being analyzed, but suggests that either a) Hagfish eyes are similar to the eyes of the first eyed chordate, or b) Hagfish eyes look so primitive because their eyes have degenerated.
Furthermore, if evolutionary biology is a big trick, then, do you have a better explanation for why life is the way it is right now, and the way life was the way it was then?
Duh, imaginary sky buddy.
MartinM says
If in one specie, eyes could not have spread to other species.
Not to other species alive at the time, no. But those species which descended from the first eyed species would inherit their eyes. That's kind of the whole damn point of common descent.
And quit bragging about your mad biology skillz; you're a fucking dentist.
Actually, my own dentist demonstrates being very well-read in biological topics, given as how earning Dentistry certification requires a thorough understanding of Biochemistry, Human Anatomy, and General Biology… Or, it may be that he just wants to show off to me whenever I have an appointment with him.
Steve, if–as your web page claims–you were a biological studies major, how did you get through an entire undergraduate curriculum without learning that the singular of "species" is "species", not "specie"? You consistently make such a trivial mistake that you don't inspire confidence in anything else you say.
Also, I'm assuming that pre-dentistry assumes a certain mathematics and science requirement. I'm curious about how you got through math with such a confused understanding of "random".
Did you get through undergraduate chemistry in order to get into dental school? Because with such a novel understanding of random processes, I'm very curious to hear your explanation of how an exothermic reaction works. It's actually quite relevant to your profession, because mixing dental plaster yields an exothermic reaction, doesn't it?
Anyhoo, if I interpret your understanding of "random" correctly, some time before the activated complex can proceed exothermically to the products, the reactants cannot proceed to the activated complex. That part of the overall reaction is endothermic, and since the reactants can't "know" in advance that the net reaction is exothermic, the endothermic part is unable to occur. After all, what good is half an activated complex?
So am I correct that you put up the same teleological objection to exothermic reactions as you do to evolution, and that you're therefore a dental-plaster denier?
Just wanted to clear that up–kthxbai!
(hopefully wrong) that you are nothing more than an anti-intellectual troll who picks fights for Jesus
Stanton, you're far more generous than I am–I ditched the "hopefully wrong" qualifier several comments ago.
I used to have a dentist like Steve, but I switched many years ago, during the AIDS epidemic in the 80s, after he sent out a postcard to his patients reassuring us about his AIDS-free status, because he was such a decent, married, Christian man. The judgmental sanctimony was so revolting, I never went back as a patient to him.
Now I'm fortunate enough to go to a sane, as well as competent and caring, dentist. When I'm there, she and I have very interesting talks about comparative dentition phenotypes in horses, sharks, and other species. She hasn't yet passed my idea for a research program (to solve the problem of teeth loss in humans by turning on the same genes sharks use to grow new teeth) on to Dental Science, but I'm sure she will any day now.
Hey Stevie,
So "why don't we figure it out?" We have. Way to not only get shown up on eye evolution, but also continue to confuse how evolution works despite the correction!
Traits, by the way, do not have to come from one species. There are many cases of certain traits evolving independently in multiple species. You also confuse how natural selection does its selecting. It's not all about devouring other species, it's about getting to resources. And being able to connect "food" to particular light levels would be an extremely huge advantage in competition for those resources over competitors that don't have that ability. Being fast, strong or healthy is irrelevant if you can't find food. Nor is every species in competition with every other species. So your mangling of my analogy on the importance of sight falls flat. But you won't hear that because [snivel]everyone is so mean to you![/snivel]
All you've produced is a long argument from personal ignorance and lack of imagination.
I've met creationists in person, and for the most part, they were all nice people, but, I just really really wished that they had the pertinent conversational skills that would have allowed them to move beyond talking at me, as well as the conversational skills to allow them to actually absorb what I say.
I would think that one problem of your idea is that the genes for teeth regeneration may interfere with the genes that regulate the number of teeth (primitive condition in mammals being 44).
Traits, by the way, do not have to come from one species. There are many cases of certain traits evolving independently in multiple species. You also confuse how natural selection does its selecting. It's not all about devouring other species, it's about getting to resources. And being able to connect "food" to particular light levels would be an extremely huge advantage in competition for those resources over competitors that don't have that ability. Being fast, strong or healthy is irrelevant if you can't find food. Nor is every species in competition with every other species. So your mangling of my analogy on the importance of sight falls flat.
When analogous traits arise in two different taxa, "convergent evolution" occurs. By comparing the traits, as well as the genes which regulate them, biologists can determine whether the two taxa are related or not, in that, by comparing the differences between the traits in question, biologists can determine whether if the two taxa are descended from another, ancestral taxon that had this trait, or if the two taxa had their own separate ancestors that different versions of that trait.
To continue with eyes, the eyes and eye-development regulatory genes of all eyed vertebrates, as well as the eye-development regulatory genes present in blind and eyeless vertebrates strongly suggest that the ancestral vertebrate had an eye with a cornea, a cupped retina and a lens.
But, this is apparently only apparent to those who actually took the time to read Professor Myers' blog entry…
When I'm there, she and I have very interesting talks about comparative dentition phenotypes in horses, sharks, and other species. She hasn't yet passed my idea for a research program (to solve the problem of teeth loss in humans by turning on the same genes sharks use to grow new teeth) on to Dental Science, but I'm sure she will any day now.
Hm. That reminded me of something I had seen a while back; a Dr. Mary MacDougall is working on the problem of gene expression and tooth generation.
http://www.webmd.com/news/20001101/what-teeth-may-come
http://adr.iadrjournals.org/cgi/content/abstract/15/1/25
Stanton,
I appreciate the extended explanation. Though, for obvious reasons, I'm trying not to use too many big words.
Yes, I imagine that's one problem my idea might have :). I was sort of joking, and sort of not–in principle, of course, the idea may possibly have some merit to it, or it may not. In theory, it may even be doable someday. But pragmatically, we still don't understand a lot about anatomy, physiology, and pathology in species much closer to us, like mice, cats, and dogs. It's going to be a long time until we connect those dots in species as far apart as sharks and humans, so one of her and my running jokes is her rolling her eyes at my "impractical" idea (and sharks, like monkeys, are always funny anyway, so we get a lot of mileage out of this particular joke).
Although (if even possible) it would still be far-off, it might actually be not quite as far-off as she and I were making it. Thanks for the refs, Owlmirror; I was not aware of them. I've now got some more very interesting reading awaiting me.
Well, thalarctos, there is always Plan B…
We get transformed bacteria to grow us new teeth in petri dishes in the meantime.
On the other hand, the eyes of larval sea squirts are said to be homologous to the pineal and the parietal organ.
(primitive condition in mammals being 44)
No, that's the primitive condition in placentals. The one for mammals as a whole depends on the definition of "mammal" and is difficult to figure out for each of those definitions.
"Dr" Stevie, who doesn't know that eyes are older than skulls in chordates and doesn't even seem to have noticed that vision isn't an all-or-nothing affair, is already gone? Too bad…
I find myself wondering if he did his biological studies from a mail-order diploma mill or similar.
His statement (on his web page) that "Humans, and all animal species, are incredibly engineered machines" started a chain of associations that linked to Dr. L. Bailey, who figured that a heart is a pump, and there was no reason not to transplant a baboon heart into a human child. When asked about this, given the baboon's evolutionary distance from H. sapiens, Bailey replied with "Er, I find that difficult to answer. You see, I don't believe in evolution."
Kseniya says
Your problem here is "equally matched". You must know that no two animals or species in nature are "equally matched". [Oh really? ~K.] Do you think a fighter who weighs is 5′ 7″ and 130 lbs.with a pair of 2% evolved eyes could defeat a blind Mike Tyson? Gimme Mike every time.
So the correct assumption is that the blind organism is always far more physically developed than the other? Ok. Let's start the list with that one, concede the victory to the big guy, but then add the other unequal matchups:
Sighted Weakling vs. Blind Tyson – Blind wins.
Sighted Tyson vs. Blind Tyson – Sighted wins.
Sighted Weakling vs. Blind Weakling – Sighted wins.
Sighted Tyspon vs. Blind Weakling – Sighted wins.
Uh… what was your point again?
Anyway, the whole Tyson vs. Weakling thing isn't consistent with the original argument, which (I assume) is based on the question of whether developing eyes confers an advantage over developing bigger, um, boxing gloves. With that in mind, maybe we should be asking if a fighter with "2% evolved eyes" would stand a chance in the ring with another fighter that was 2% taller and 2% heavier. I'd take the sighted fighter every time.
Sigh. I feel stupid now, having even contributed to this line of thought.
Nonsense! You only took a silly potshot of mine and refined it into a clearly pointed argument. The truth remains the same, but now I'll have to up with other throw away lines.
"Dr" Stevie, who doesn't know that eyes are older than skulls in chordates and doesn't even seem to have noticed that vision isn't an all-or-nothing affair, is already gone?
I, for one, am going to be very disappointed if he skitters away without answering my question about dental-plaster denialism.
Oh, well, FtK and Testytestacci never answered my questions, either. Seems to be a habit among them.
Some lovely gems from Dr. Steve's website:
I have absolutely no idea how species came into existence, and I don't promote any solution to that great and fascinating puzzle.
So… he's not even a creationist? All animals in their endless forms… just are? There's no relationship between any of them?
That's got to be the dumbest thing ever.
No, I should take that back. I'm sure there's something even dumber and more contradictory that will turn up.
There's also this:
There appears to have been some minor evolution that has taken (takes) place.
So evolution is indeed a fact? And he's arguing against it… because?
And a few sentences later:
Origins of species is an incredible subject, but it is also a useless science. No cures for disease or mechanical marvels will be produced by it.
So those drug tests that use animal models are "useless", because there's no relationship between our species? And the newer antibiotics that deal with strains of diseases that have evolved resistance to older antibiotics are "useless", or don't exist?
Somebody's confused.
Rey Fox says
Yep. Just once, I wish these guys would quit while they're behind.
Maybe he's a satirist?
And… LOL @ "dental-plaster denialism." :-)
Thanks, Kseniya :). That's actually the example that got me out of thinking like a creationist–well, not dental plaster specifically, but exothermic reactions in general.
I was always a math geek, and did high-school chemistry and physics, but avoided biology as too "soft" a science, so I never got a good basic grounding in that until grad school. Of course, I had heard the term "evolution", and didn't have any problem with it at the term level, but I had no real understanding of it, either–it just "was".
Exothermic reactions finally got me to understand randomness and population distributions. When we first analyzed the energy profile of exothermic reactions, I was really mystified how the molecules "knew" that, if they just made that little endothermic "investment" upfront, it would "pay off" for them exothermically afterwards.
I broke my head against that one for quite a while before eventually figuring it out (and how long *that* took is not exactly one of my prouder intellectual moments, :). So even though I had no beef with evolution, I was still at that point thinking like a creationist, and coming to the same type of wrong conclusions.
I'm feeling much better now, though.
If they knew enough to quit while they were behind, they wouldn't be out and about on the Internets making colossal, booby-headed boobs out of themselves in the first place.
Why not have some chicken soup and discounted Valentine's Day candy to help, too?
Dr. Stephen Thomas says
Wow. I sure stimulated a lot of writing. We are going in circles, and there are sure more interesting things to spend time on. Actually I occasionally search evolution sites in hope of finding new information, and further educating myself on the subject, which is how I came to this site. But the more I do, the more I find reasons, for me, that the TOE is not how thing came down. I think it's REASONABLE to doubt that 250,000 random mutations could "easily" (Dawkins) bring about the evolution of vision, when there was absolutely no "vision" model on the planet earth. And the retina-optic nerve system had to concoct an incredibly complex code to send to the vision centers of the brain which then were required to "evolve/learn" to decode to form the amazing images that we see. These steps are complex beyond imagination, but not listed on this site. And I simply don't see how M and NS could accomplish such an incredible feat. For this and many other reasons I certainly think that my doubt about the TOE is, again, reasonable.
It seems really strange that one thing I don't see in the world of evolution is any questioners. It seems that evolution believers accept everything with an amazing amount of dedication and "blind faith". Don't you guys ever wonder or doubt just a little bit about the TOE being real?
So we will just put it down that you folks are believers, and I am not. And, Stanton, I don't have a theory at all about how species appeared. I wish I could come up with something, but I simply don't think there is enough information. (I know, you do.) But I will try your book. I do enjoy the read, even though I do read with a doubting eye. To ME it seems that there is something in nature that we just haven't figured out yet.
And, MAJeff, no I don' think it's "Duh an imaginary sky buddy".
And thalarctos, just to make you happy on the plaster denialism thing: wow, very clever.
Well, adios. And if you do come up with any amazing evidence that the TOE is how this whole thing happened, please contact me on my site if you like. I really am obviously very interested.
Dr Stephen Thomas:
If you actually read about the Theory of Evolution, you would realize that it does not address how life first arose, it addresses how the diversity of life came to be, and changes due to the fact that the offspring of organisms tend to be imperfect copies of their parents. Personal incredulity can not negate the fact that Evolutionary Biology is among the most, if not the most heavily supported science currently known to Mankind. Furthermore, Evolution, i.e., "descent with modification from generation to generation," has been observed occurring laboratories, gardens, farm-fields, greenhouses, terrariums, aquariums, kennels, aviariums, ponds, and in the wild by scientists, farmers, gardeners, orchid and flower fanciers, and animal breeders for several thousand years. Alfred Wallace and Charles Darwin just happen to be the first two people in recorded human history to sit down and write about an explanation to why life was so diverse, and why people were able to create so many breeds of pigeons.
If you actually read Professor Myers' blog entry, you would realize that eyes are derived from nervous tissue that budded directly off of the brain, and are covered in tissue derived from skin tissue.
If you actually took the time to take classes in Anatomy and Physiology, you would realize that any organ or tissue can become a sensory organ if it is cable of stimulating nerve endings connected to it.
So, in other words, Dr. Stephen, please, please, please, sally forth to read, study and ask for help in understanding Biology (Evolutionary or otherwise) before you elect to make judgments by glorifying your own ignorance.
wow, very clever
Yes, it was, thank you.
And you don't have the least intention of addressing the issue it raises, do you?
Unless he intends to manipulate and or pervert them into more strawman fallacies, it's highly unlikely he will make even a 2% hearted attempt to address them.
Creationist trolls are almost always like that.
I think it's REASONABLE to doubt that 250,000 random mutations could "easily" (Dawkins) bring about the evolution of vision, when there was absolutely no "vision" model on the planet earth.
What do you mean, "no vision model"? Are you not aware that single-celled protozoa, for example, can have light-sensitive structures that use the same sorts of chemicals (opsins) used in higher-order organisms?
And I simply don't see how M and NS could accomplish such an incredible feat.
How much have you read on mutation and natural selection?
You express incredulity, but offer nothing to suggest that you've even read this blog post in its entirety, let alone the actual paper that it's based on, or any other scientific paper, or even a science book on evolution and genetics for the masses.
Given that you have no other theory to offer, and your demonstrated lack of knowledge, your vague statement about "something in nature that we just haven't figured out yet" is either a truism (we haven't figured out everything about evolution, which is why biology is still a thriving science that investigates nature), or is completely meaningless (in that you are trying to imply that there is something supernatural going on).
You evolution believers pretend that you don't like trolls, but in reality you love it. You love the subject and the debate, just like I do. Otherwise you wouldn't be here. The only reason that I do what I do is a great personal interest and fascination with the subject. My blog started out as just a couple of personal posts. At the beginning I was ambivalent about the subject. As I read more, studied evolution sites, and went to university evolution lectures, my thoughts about the subject changed to the negative. The number of pages grew and also *evolved*.
If someone comes on this (or any) site and challenges your beliefs, you guys come out like piranhas after the prey. Anyway, I have been thoroughly attacked and demeaned, which is what evolution believers do best when facing challenges. That's fine, expected, and, the norm. You have little evidence of who I really am, (or what I have read). You bend the evidence that you do have to fit your needs.You are able to construct an incredibly detailed model of what you hope I am. This is the perfect example of evolution science at its best.
So let's just leave it at that. Of course I would like to answer the last posts, but doing so is like trying to catch a greased fully evolved pig running around in circles. Since you wrote so much, I just wanted to acknowledge that your comments have been duly read. Keep on believing. And, whatever you do, never question.
The fact remains that all of your posts strongly suggests that you either are physically incapable of understanding Evolutionary Biology, or that you refuse to understand Evolutionary Biology. Either way, your claims of having allegedly reviewed the evidence of Evolutionary Biology and found it wanting are highly suspect, given as how this blog entry succinctly explains eye evolution. I suspect that you are too lazy and too stubborn to attempt to understand Evolutionary Biology.
Furthermore, the regular commenters do not like trolls. They are driven to agitation by arrogant idiocy, especially the idiocy trumpeted by evolution-denying trolls like yourself, in the exact same manner splashing in a piranha school's mating grounds will drive the school into frenzy.
The only reason that I do what I do is a great personal interest and fascination with the subject
which subject? trolling the internet?
'cause otherwise, if it's anything to do with biology, you seem woefully ill-informed for it being a subject of great personal interest.
so, what exactly is your interest in there, doc?
Anyway, I have been thoroughly attacked and demeaned, which is what evolution believers do best when facing challenges.
Your "challenges" have been obvious misconceptions. And when challenged in return — to demonstrate your actual knowledge and reading comprehension — you bluster and offer a few paragraphs about how offended you are.
Shrug. You've got nothing.
Of course I would like to answer the last posts, but doing so is like trying to catch a greased fully evolved pig running around in circles.
Straightforward question, no greased pig, nothing else, just this–since your logic would preclude exothermic reactions, and since exothermic reactions do actually occur, doesn't that contradiction show that there's something wrong with your reasoning?
And, whatever you do, never question.
Oh, no worries, I'm questioning all right. Apparently, your motto for yourself is "never answer".
Did I just read what I think I read, or did this guy really just admit to being a troll?
And after admitting being a troll this whole time, he then continues to play the offended card that he's been treated, well, like a troll.
I'm having difficulty finding way to express a thought process such as this.
Troll Question: Did eyes evolve in (A) one single species, or (B) did they evolve in thousands/millions of species at the same time in unison?
Answer: (A) (MartinM) Not to other species alive at the time, no. But those species which descended from the first eyed species would inherit their eyes. That's kind of the whole damn point of common descent. (one single species)
Answer (B) (Stanton) Among other things, fossils of the earliest recognized chordate, Haikouella, from 525 million years ago, show that chordates developed primitive, very simple eyes very early in their history. (multiple species)
Answer (C) I can't think of any good reason not to make fun of someone as pig-headedly stupid, ignorant, and arrogant as yourself.
Answer (D) Somebody's confused.
Answer (E) So, in other words, Dr. Stephen, please, please, please, sally forth to read, study and ask for help in understanding Biology (Evolutionary or otherwise) before you elect to make judgments by glorifying your own ignorance.
Answer (F) All you've produced is a long argument from personal ignorance and lack of imagination.
So, in other words, Dr Steve, you are nothing more than an arrogant troll who is arrogant enough to be content wallowing in his own stupidity.
Did eyes evolve in (A) one single species, or (B) did they evolve in thousands/millions of species at the same time in unison?
The answer is "yes". Mostly.
The trait of very simple eyes originally arose in one single early multicellular species. However, as that population continued to evolve and speciate, the eyes of the different species populations continued to evolve as well.
This was before chordates split off from invertebrates, though. The blog post — which it certainly looks like you still have not read — is about the evolution of the eye among all chordates, inherited from the common chordate ancestor. Different chordate species then evolved different complex eyes.
Although I should add that the answer is "no" to the very last part of the question. No two different chordate species evolved eyes "in unison", since only populations of the same species could evolve in the same way. Once the species diverged, so too did the evolution of their eyes. Although there is sometimes convergent evolution of similar-looking traits, when the individuals of a population are examined at a closer level (sometimes necessarily at the level of the genes), the genetic changes that led to the similar traits turn out to be very different.
Just out of idle curiosity, did your alleged instruction in biology include any mention of the homeobox or HOX genes? No, wait, don't answer that.
Excuse me, that wasn't in response to your troll question, but in response to your troll webpage. But hey, don't clarify what you mean by your statements.
I remember that quote! I smile reading it now. It's just so… true.
But this was of course in response to your many statements that you do not and cannot grasp how such evolutionary processes could happen, in spite of the in-depth explanations as to why it can.
Not in reply to your aptly titled: Troll question.
But hey, I do love the quote-mining! It shows that you put that little bit extra into being dishonest. Well done.
Stanton: What do you mean, "no vision model"? Are you not aware that single-celled protozoa, for example, can have light-sensitive structures that use the same sorts of chemicals (opsins) used in higher-order organisms?
T: Kind of like a two by four being the model for the Sears Tower? Only an evolutionists would think that opsins in a protozoa are good modeling for a binocular vision system. Stanton, please, please take a course in logic and common sense.
Owlmirror: How much have you read on mutation and natural selection?
Lots. But do I believe it? No.
Owlmirror: You express incredulity, but offer nothing to suggest that you've even read ……any other scientific paper, or even a science book on evolution and genetics for the masses.
Critiqued on my site: "The Blind Watchmaker", Lecture by Dr. Francisco Ayala, evolution websites explaining eye/heart evolution. Others, but no more room.
Owlmirror: You bluster and offer a few paragraphs about how offended you are.
T: I never said I was offended. It doesn't bother me at all. I said your demeaning of me and a reasonable question are completely normal and expected for evolutionists.
Stanton: Furthermore, the regular commenters do not like trolls.
T: Obviously evolutionists like to exist inside of their protective bubble where everybody happily agrees with each other. And they are compelled to force their ideas on others. Kind of reminds me of church! Good science should be able to answer reasonable challenges and questions and should be happy to do so. No other science would treat questioners like evolutionists do, but, as I said, it's expected. Anyway, this will be my last entry (Yay!). I swear to the big invisible sky buddy. You (pl.) can go about patting yourselves on the back without me interfering in your club.
Ichthyic: What exactly is your interest in there, doc?
T: My interest is simply an intense interest.
To Owlmiller: Thanks for the most reasonable answer of the commenters. You started out the worst, and wound up as champion. It's easy to say how things happened, I just simply have too much trouble visualizing and accepting them.
My problem is I can't visualize how 250,000-400,000 mutations could be divvied up amongst the twenty five or so parts of the eyeball, plus the optic nerve, biochemical code, thalamus, and visual cortex. Thousands of group mutations would have to be assigned to each part of the system. (about 10,000 to each part?) If a mutation started the retina, later mutations would have to add to what the earlier mutation did. Kind of like a team effort. Also, considering the fact that according to evolutionists, 50% of mutations are not "good", each mutation would have to be accompanied by a "bad" mutation, which would mean one step forward and one step back, and zero steps to eyeballhood. Would 1/200,000 of an eye be a benefit to an individual that would help him survive?
The idea of this scenario happening in just one specie is unthinkable. The idea that the same unbelievably unlikely scenario of eye evolution happening in multiple species all at the same time, while so many other body parts and organs are also evolving in the same fashion, well…………………
Anyway, farewell. Debate is rather addicting for me so I have to go cold turkey here. I'm sure (hope?)you are all a lot nicer in person than your comments show. I will leave you to your protective bubble. You have done some very thorough and complete demeaning above, so hopefully you won't waste any more time on me. (And I am NOT complaining.)
I am not the one with the inability to absorb information, Steve.
Please do not let the door hit your fundament on the way out, and I hope that your patients do not bite you when you stick your hand into their mouths.
Y'know, Steve, I didn't want to bring it up before because at first it seemed to be trivial, but you seem to be demonstrating that you have a real problem reading. I don't just mean the complexities of evolution, here. You appear to not be paying attention to how comments here are attributed. It wasn't Stanton who wrote about opsins in protozoa. That was my comment.
And in your comment 76, it sure looks like you took my comment at 73, and thought that I was also the one responding in comments 74 and 75. Please go back and check; 74 and 75 were by a commenter called "truth machine", not me.
And further down, it sure looks like you thought that the commenter "Michael X" was me; you prefixed his words in your response with an "O:".
Each comment ends with the phrase "Posted by:", and then the name the commenter uses. You've used "Dr. Stephen Thomas" and "stevebee92653", but it's been obvious that you're the same person because you keep using that silly "www.evillusion.net" URL. OK, fine. But everyone commenting here is a distinct individual so far as I know, and we all have been using unique and distinct names to sign off on our comments.
I don't know if you have a visual problem, or a visual processing problem, or an attention-deficit problem, but it doesn't help your arguments when you get really, really, basic things wrong, such as the names of the commenters that you are responding to.
Owlmirror, I get the distinct impression that "Dr" Steve has become comfortably numb to his information-processing problems, and no longer cares if they are the reason for his inability to understand, if he even cares to recognize that he has a crippling problem to begin with.
Dr. Steve says
How were 250,000-400,000 mutations divvied up amongst the twenty five or so parts of the eyeball, plus the optic nerve, biochemical code, thalamus, and visual cortex. Thousands of group mutations would have to be assigned to each part of the system. (about 10,000-20,000 to each part?) If a mutation started the retina, later mutations would have to add to what the earlier mutation did. How did it know what to mutate? Kind of like a team effort? Also, considering the fact that according to evolutionists, 50% of mutations are not "good", each mutation would have to be accompanied by a "bad" mutation, which would mean one step forward and one step back, and zero steps to eyeballhood.
Ha-ha! Steve thinks that by reciting the names of various body parts and spewing numbers, he'll be taken seriously as a 'doctor.'
Perhaps the good doctor might build himself a bamboo control tower and land himself a plane fulla cargo.
How did it know what to mutate?
How do reactants in exothermic reactions (such as dental plaster) "know" to go endothermic to form an activated complex?
If you can answer my question, you'll have answered yours.
Thomas Moss says
"Thousands of group mutations would have to be assigned to each part of the system. (about 10,000-20,000 to each part?)"
I am not quite sure if the exact numbers given are correct, but the general idea is. A lot of mutations would be needed. This is one of the reasons evolution takes such a lot of time.
"If a mutation started the retina, later mutations would have to add to what the earlier mutation did. How did it know what to mutate? Kind of like a team effort?"
It didn't know how to mutate, and it didn't need to. Mutations just happen, some of them good, and some of them bad. This is where natural selection comes in, causing the good mutations to spread throughout the populations and the bad ones to die out. Evolution does not work towards some predetermined goal, it just works with whatever it has with each and every step being an improvement over the last.
"Also, considering the fact that according to evolutionists, 50% of mutations are not "good""
Actually, it's even worse than that. Most mutations have no effect at all (they just change the spelling of the genome, like how 'color' and 'colour' mean the same thing). Of those which do have an effect, most have a bad effect. They eye is already pretty good, so any change is likely to be bad. This is why mutation alone cannot cause evolution to occur – selective forces are needed, too.
" . . . each mutation would have to be accompanied by a "bad" mutation, which would mean one step forward and one step back . . ."
Yes, with natural selection keeping the steps forward, and discarding the steps back, leading to overall progress. Of course, this progress is best seen as change in such a way that each step is better than the last, not movement 'forward' as if towards some predetermined goal.
". . . and zero steps to eyeballhood."
Overall, mutation by itself would lead to zero steps toward eyeballhood. A combination of mutation and selective forces is what drives evolution.
"Doctor" Steve has deliberately blinded himself to recognizing this particular fact that we have been futilely trying to point out to him repeatedly.
Despite this, Steve has the gall to allege that we are somehow stupid and he somehow smart because of this situation.
Thomas Moss made a pretty good reply, but I thought I'd focus on this particular point a little more.
Also, considering the fact that according to evolutionists, 50% of mutations are not "good", each mutation would have to be accompanied by a "bad" mutation, which would mean one step forward and one step back, and zero steps to eyeballhood.
This is a fundamentally confused idea of how random mutation works. Given the size of the various multicellular genomes, a given random mutation will most likely affect only a single trait. And because of DNA recombination during meiotic cellular division, a positive mutation on one particular chromosome can be swapped in while a negative trait elsewhere is swapped out (or just not included). If the negative traits are truly harmful, they will be selected against; those offspring that have them will die without reproducing. But even negative traits are often dependent on environmental context.
So, my point is, for various reasons, mutations that occur are almost never going to have equal and opposite effects to each other. There's nothing in any biological work that suggests that they would, and there's a lot that explains why they wouldn't. Where did you get the idea that they would?
Steve, you've said that you've studied biology, but I keep seeing in your arguments the strong implication that you either didn't read them, or didn't understand what you read.
Do you still have your biology texts? Can you go back and read about what mutations are and how they occur?
This is all pretty basic stuff.
My question: How were 250,000-400,000 mutations divvied up amongst the twenty five or so parts of the eyeball, plus the optic nerve, biochemical code, thalamus, and visual cortex. Thousands of group mutations would have to be assigned to each part of the system. (about 10,000-20,000 to each part?) If a mutation started the retina, later mutations would have to add to what the earlier mutation did. How did they know what to mutate? Kind of like a team effort?
Brownian, OM: Ha-ha! Steve thinks that by reciting the names of various body parts and spewing numbers, he'll be taken seriously as a 'doctor.' Perhaps the good doctor might build himself a bamboo control tower and land himself a plane fulla cargo.
thalarctos: How do reactants in exothermic reactions (such as dental plaster) "know" to go endothermic to form an activated complex?
Thomas Moss: I am not quite sure if the exact numbers given are correct, but the general idea is. A lot of mutations would be needed. This is one of the reasons evolution takes such a lot of time. It didn't know how to mutate, and it didn't need to. Mutations just happen, some of them good, and some of them bad. A combination of mutation and selective forces is what drives evolution.
Stanton: "Doctor" Steve has deliberately blinded himself to recognizing this particular fact that we have been futilely trying to point out to him repeatedly. Despite this, Steve has the gall to allege that we are somehow stupid and he somehow smart because of this situation.
Owlmirror: Steve, you've said that you've studied biology, but I keep seeing in your arguments the strong implication that you either didn't read them, or didn't understand what you read. Do you still have your biology texts? Can you go back and read about what mutations are and how they occur? This is all pretty basic stuff.
Me: These are some fine answers to my question! And remember, the same question must be posed and answered for every other biological organ and system for the TOE to have any veracity. The reality here is that none of you, nor any evolutionaut on earth, can answer it. So don't feel too bad. It shows that things couldn't have happened they way the TOE says it did. You can keep answering by demeaning me, (that's fine with me), ignore me and I will surely go away (I will, and sorry, I had to take a peak one more time), or do some objective and real thinking on your own about just MAYBE the TOE is not the solution to the Puzzle and then work on a more logical model. (I'm not too hopeful on that.) Of course I don't have a new model; I wish I did. I am at least smart enough to know that I don't have enough intelligence to figure it out. And I am also smart enough to know that no one who now lives or ever lived on the planet earth including Darwin and Einstein has/had the intelligence to figure it out either.
Those of you who repeatedly say I should study a biology text must know they are laced with TOE, and they would not answer any of my questions anyway, just like you piranhas haven't. And you have to know that I am very well read on the subject, even though you keep up the demeaning banter. Stanton, I have never alleged that anyone was stupid. The more I have studied, the more it shows TOE is not how things happened. And, Owlmirror, of course I know what mutations are. Are you kidding? And, sorry, thalarctos, I get your drift with exothermic reactions, but they just don't do anything for me in regard to the questions I have posed.
Obviously anyone interested in the origin of species and life on earth must have a high level of intelligence. I have no idea why any of you are so interested, or who you are, or how you are so connected to this site which I was directed to by TO. You have that advantage over me, as some of you have seen my background and photo (ugh) and my thoughts on http://www.evillusion.net.
My question: why the fuck doesn't stevebee go read a fucking textbook instead of cutting and pasting the same rants in thread after thread? Does he honestly think we're as dumb as he is to not see through his concern troll game?
Steve: go play in traffic. You're not worth the effort, and at this point in your life, if you haven't figured out how to read and learn on your own, all you are is an extra source of carbon dioxide in a world that's already overheating. We can no longer afford your kind. You're a useless human being, and as such, you're becoming a significant liability to us all.
So, um, if you're ever touring a big meat packing plant, and you're like, walking the catwalk above the big sausage rendering vats, go ahead and don't listen to the tour guide's safety instructions. The biggest contribution you'll probably ever make to the world is part of one of the 'E's in Oscar Meyer.
How did they know what to mutate? Kind of like a team effort?
Nope, don't even need to answer that. The assumptions of the question answer themselves. Go away Steve. You're just being a pest now.
He is tenacious though, yeah? Like a rat that keeps touching the electrified wall again and again, no matter how may times it's shocked. Steve just isn't going to get it at this point. At least not here. I think a personal tutor might help.
And, Owlmirror, of course I know what mutations are.
No, Steve, you don't. You don't understand genetics, or inheritance, or meiosis, or reproduction, or mutations. Your ignorance was demonstrated by the way you've been phrasing your statements and questions. This is basic information covered by any biology textbook. You either have not read basic biology, or you haven't understood it.
Your problems with comprehension and reasoning are also demonstrated by calling the theory of evolution "illogical". The theory of evolution is based on some very simple and basic observations:
Offspring vary from their parents.
Variation can be inherited.
Inherited variations that enhance survival and reproduction in some environment will allow those offspring that have them to bear more offspring that will have those survival and reproductive-enhancing traits.
Now, can you honestly say that any of the above are "illogical"? Have you ever known offspring that were absolutely identical to their parents? Do you have reason to believe that variations can never be inherited? Can you think of some situation where offspring which are less able to survive and reproduce would nevertheless survive longer and reproduce more?
All of evolutionary biology is based on the basic ideas. Modern biology is still studying how variation arises, and how organisms interact with their environments, and with each other. The details of evolution are not simple, but the basics are eminently logical, and based on observation.
Once again, I recommend going back and studying those basics, and gaining a better understanding of the details.
Those of you who repeatedly say I should study a biology text must know they are laced with TOE,
Well, yes. In the same way that chemistry texts are "laced" with atomic theory, or astronomy texts are "laced" with geometry and optics.
And, sorry, thalarctos, I get your drift with exothermic reactions, but they just don't do anything for me in regard to the questions I have posed.
The fact that you can't connect the dots when they're jumping up and down right in front of you demonstrates very clearly that you *don't* get my drift, or really much of anything else about biology.
Not surprising, really–we're talking, after all, to someone who vaunts his undergraduate biology study, yet doesn't know that the singular of "species" is not "specie".
I really don't know why you keep coming back here where people see right through you. There are a lot of uninformed trusting marks out there elsewhere for you to practice your biology con on; I'd think you'd find that a lot more gratifying than continually making a jackass of yourself here.
The subject WAS: Can Mutations and Natural Selection Form the Visual System (I say no,you say yes.)
The subject WAS NOT: Do Populations Vary from Generation to Generation (I say of course, you say the same.)
Bye again, again………….
They're actually the same subject, underneath. Populations vary from generation to generation, and the ones with the variations that best enable them to survive will propagate. This includes variations in tissues that are light-sensitive.
You're saying "no", not because you have some massive advanced knowledge of genomics and developmental biology that gives you some special insight, but because you don't know or understand the evidence from genomics and developmental biology.
Really, you're like that editorial writer in the NY Times who said that rockets are useless to reach space because above the atmosphere, there would be nothing to "push against".
They're actually the same subject, underneath.
Of course, you need to be capable of surpassing rote memorization to thinking outside the leaf node for that insight, a challenge which a lot of otherwise intelligent-seeming creationists don't seem to be able to get past.
Had I worlds enough and time to take on another research question, I'd look into why that is–it's a quite intriguing–oh, I don't know, maybe psychology of education(?)–problem. Why do abstraction and ability to form connections among ideas "take" in some kids, and not in others, even though the latter are seemingly bright enough and have progressed quite far in school?.
"This includes variations in tissues that are light-sensitive."-Owlmirror
One problem for your "light sensitive tissues": light was nonexistent before at least one full visual system had evolved, minimally composed of retinas, optic nerves, and a visual cortex. The earth before a complete visual system was formed was completely dark. Not black, but pitch dark. The Sun and all stars don't produce light at all. They produce electromagnetic radiation of differing wavelengths. EM radiation with a wavelength between approximately 400 nm and 700 nm is detected by the human eye and perceived as visible light. EM radiation stimulates the retina, which sends an unbelievably complex signal to the visual cortex. Light, color, and visual images are completely manufactured in the visual cortex from this signal, and don't exist outside of a brain and visual cortex at all. I realize that evolutionists think vision was an easy engineering project for M and NS; all they needed was time. And that there was/is light all over the place, and all a species had to do is form eyes like the paper describes on this site, let the light in, and there would be vision. In reality, M and NS would have had to know that by treating electromagnetic waves in an unbelievably complex fashion, which scientists are not even close to understanding, light, color, and visual images would be the result. How did M and NS know what it needed to do to produce vision? I must admit I don't really understand mutations, because I just don't see how mutations could form a visual system. I'm glad that you are so incredibly intelligent and you do. But, for accuracy, I would quit calling cells that supposedly led to a complete vision system "light sensitive" since there was no light. And, of course, "electromagnetic radiation sensitive cells" would be pretty worthless to a host. But I am sure you can "connect the dots", and think of lots of advantages. And, I am sure you are aware of all of this information. It just isn't discussed in this paper, for some reason.
wazza says
Ugh. I don't want to respond to such stupidity, but the day we give up fighting for the truth is the day you IDiots win.
Light existed before there were eyes to see it, and playing with semantics won't change that. Another way to define light is "wavelengths that pass through air, but are reflected by most solid objects, and can act on chemical systems in a detectable way". That's why we only detect these wavelengths and not others; because they're useful.
So, we have this light coming from the sun, passing through the atmosphere and water to this little blind worm. And one day a mutation alters one of its proteins to be light sensitive. This is plausible; many proteins are light sensitive without being involved in the eyes. So our worm finds some of its cells, those that express this slightly changed protein, feel different to others when pointed in a certain direction, namely, towards the light. This might persist as just one of the features of a random protein… until it becomes useful, that is. And it is useful, because in the ocean, light means surface. Finding the surface is helpful. So this mutation is selected for.
Once you've got that, random changes in any way, coupled with heritability, can produce a human-style eye in 100000 generations. That's probably only a couple of millenia for an ocean-dwelling worm with a fast life cycle. You can find a paper on this on the internet.
Anyway, the evolution of the eye's an easy one. The visual impression received from the eye would probably evolve more slowly, but after all, there are billions of years in which to do it. In any case, your objections are spurious, and your attempt to wrap it up in pseudoscientific garbage in order to make it harder to refute is just childish.
How did M and NS know what it needed to do to produce vision?
The same way that the components of dental plaster "know" that if they initially go endothermic, they will get the "payoff" in the form of an exothermic reaction down the line. We've covered the same ground many times, and you keep asking the same questions over and over again.
Let's try a clinical application of probability, to see if you can possibly understand it in those terms. Five years ago, I had a blood clot that took out 3 feet of my small intestine. I was put on coumadin (a blood thinner, originally a rat poison–interesting story for another time) after I got out of the hospital.
Since I had the entire panel of tests for genetic causes of coagulation disorders, and tested negative for all (known) causes, my hematologist was comfortable with my taking coumadin for a year or so, but *not* for life. As he put it, let's say my yearly risk of a hemorrhagic stroke from too much bleeding from the blood thinner is 1-2%. For a year or two, that doesn't add up to much, but as a 44-year-old (at that time) woman, let's assume I have another 30-40 years to live. A yearly risk of 1-2%, over a period of 30-40 years, adds up to more of a lifetime risk of hemorrhagic stroke than he feels justifies taking coumadin in the absence of any known genetic risk factors.
Do you follow his clinical reasoning in making that prescribing recommendation? And if so, would you then find it reasonable to ask "How does coumadin know what it needs to do to produce hemorrhagic stroke?"
If your answer is "yes", well, we're clearly both wasting our time. And if your answer is "no", then what is the difference between that question and your previous one? Assuming the "yearly risk" of any organism's developing light sensitivity is extremely low, what is the "lifetime risk" of that organism's developing light sensitivity over millions of years?
If you can understand that clinical reasoning, then you can understand why the question you insist on repeating in terms of "knowing what to do" makes no sense.
The earth before a complete visual system was formed was completely dark. Not black, but pitch dark. The Sun and all stars don't produce light at all. They produce electromagnetic radiation of differing wavelengths.
This is so much semantic nonsense. What the hell is wrong with your brain, that you are suddenly insisting on denying the basic common meaning of the word "light"?
How confused are you, to start blathering that "light was nonexistent"? And calling it "electromagnetic radiation", as though that makes you somehow "smart"? For pity's sake, the nature and composition of sunlight was being analyzed long before anyone knew that it is electromagnetic radiation, or was able to measure what its frequencies are in nanometers.
How do you expect to have even a basic discussion when you are being so utterly intellectually dishonest?
And your line about "retinas, optic nerves, and a visual cortex" has already been addressed. Single celled organisms exist that are light-sensitive. All they need is the chemicals that reacts to light. Or, if you want to be sophomoric about it, chemicals that react to electromagnetic radiation between 300nm and 1100nm.
And, of course, "electromagnetic radiation sensitive cells" would be pretty worthless to a host.
You're thinking about the whole thing exactly the wrong way around.
We are not "hosts" that just happen to have light sensitive cells. We are the descendants of collections of cells, combining and cooperating by the use of chemical signals, and using chemicals internally, some of which happen to be light-sensitive. All that is necessary is for the light-sensitive cells to only give off specific signals when light is received, in different concentrations according to the intensity of the light, and for other cells to receive those signals, and react accordingly. The whole complex visual system has to start from something very basic, but the very basic is terribly simple.
But I note, in all this confused questioning about the origins of the visual system, that you don't seem to be challenging the idea of the evolution of a visual system once it exists.
Do you, therefore, concede that once an organism has "retinas, optic nerves, and a visual cortex", that that visual system can then evolve?
If Dr Thomas actually knew how to read, he would have realized that "visible light" is a very small section of the electro-magnetic wavelengths.
If Dr Thomas actually knew how to read, he would have known that even microorganisms, such as Euglena, have photo-sensitive which help them to orient themselves toward (sun)light. In fact, it's very easy even for blind organisms to orient themselves toward light, given as how sunlight also contains heat energy.
I'm appalled that a person like Dr Thomas can assume the title of "Doctor," and yet, be so arrogantly entrenched in his ignorance.
So long has there been radiation, there will always be light of some form or another.
Sight in animals is intimately tied to the origin of pigmentation, and its first use in living organisms to protect themselves from radiation, such as ultraviolet and visible light. Radiation is potentially dangerous to organisms because it can damage DNA, and cause proteins to denature. First off, the first pigments arose as waste products from various metabolic processes, such as the way the pigment melanin is produced at the end of tyrosine kinase metabolism. And as such, those first microorganisms that colonized sunny areas were able to protect themselves from sunlight by producing lots of pigment. Second, when a molecule of pigment absorbs radiation, it degrades. Often, it will initiate a complex chain reaction, such as what happens when chlorophyll absorbs a photon to use carbon dioxide and water to eventually form a molecule of sugar. Other organisms use other pigments to initiate other chain reactions, such as the archaean Halobacter using its pink pigments to make ATP.
But I digress: If an organism can detect heat, it can also detect sunlight even without the aid of specialized light-sensing organs, in that a blind maggot will move out of the light, whether the light comes from a flashlight, the sun, or a heat lamp. Pigments are produced by organisms as waste products of other metabolic processes, and have been used by organisms to defend against the harmful effects of light and radiation.
Having said all this, all that is needed to create a light-sensitive organ is to hook a nerve-ending up to a cell or cells containing light-sensitive pigments, such as rhodopsin. As the rhodopsin is degraded by absorbing photons, and is replaced, it generates an action potential, which, in turn, will set off the nerve ending. And the most primitive eyes happen to be nothing more than rhodopsin-manufacturing cells.
…the most primitive eyes happen to be nothing more than rhodopsin-manufacturing cells that are hooked up to nerve endings.
Don't you mean egnorance, Stanton? :)
As for the title, it's not like dentistry is a research degree or anything (although I do know some fine dental researchers), but I admit to a certain amount of curiosity as to whether he'll be able to at least follow a clinical reasoning example of probability.
Thalarctos, it's my opinion that dentists should be very intelligent people, if only because I always compare every dentist I meet or hear about to my family dentist. And my dentist is an extremely intelligent man whom I've been verbally and mentally fencing with since before I can remember.
And to feel the palpable willful ignorance, pardon, willful egnorance that oozes out of all of the smarmy and inane comments posted by this "Dr" Stephen Thomas is horrifying enough, but, to hear that he's a dentist who puts his grubby little fingers into the open mouths of hapless people…
How to describe the feeling I get from reading his stupidity, while also learning that he's (allegedly) a dentist in English? Is there a word in English that describes the sort of feeling a person gets when he finds out that that lovable little old lady who loves kittens loves putting live kittens in a sausage maker?
Comparing my dentist to "Dr" Stephen Thomas isn't like comparing a diamond with a lump of coal, it's like comparing a diamond with a shard of broken plastic.
Wazza: In the first sentence you call me stupid and an idiot. Please read what you wrote: "…the evolution of the eye is an easy one." "It evolved in 100,000 generations." Just keep saying to yourself "this is plausible" so you can continue believing.
Thalarctos: You continually compare evolution of an unimaginably complex visual system to endothermic reactions. Sorry, but that's not worthy of discussion. And now "How does coumadin know…?" Somehow that doesn't reach the level of mutations forming retinas, optic nerves, a visual cortex, eyelids, lenses……………either. But if in your mind it does, great for you!
Owlmirror: SunLIGHT was being analyzed by individuals WITH visual cortex's and the ability to see color and images. Your retina takes EMR and translates it into a code which is translated by the visual cortex into light, color, and visual images. No cortex, no color, light, or visual images. Tough concept, but if you really think about it, you will get it. Try, "If a tree falls in the woods……….." No observer with equipment, no sound, no light. Recommended reading: Symbiotic Universe by George Greenstein.
Stanton: I gave you the narrow range of visible light in my comment. Can't you read? Maggots that move away from EMR and microorganisms that have photosensitive anything is certainly great evidence for the evolution of a binocular visual system. "All that is needed to CREATE a light sensitive organ is to hook up a nerve ending…." Right. A very simple task. You better do a word search. CREATE is a very scary one. You might get fired. BTW, how did you know my hands were little and grubby?
Yes, as I suspected, a clinical reasoning example would stump you. I wonder if it's too late for you to get your money back on all those vaunted undergraduate biology courses of yours.
Thalarctos: You continually compare evolution of an unimaginably complex visual system to endothermic reactions. Sorry, but that's not worthy of discussion.
If it's that obviously not worthy of discussion, surely you should be able to demolish my logical and evidentiary flaws in a sentence or two, with references to the appropriate literature. Don't just leave us hanging, now–please explain the difference.
And now "How does coumadin know…?" Somehow that doesn't reach the level of mutations forming retinas, optic nerves, a visual cortex, eyelids, lenses……………either. But if in your mind it does, great for you!
"Somehow"? Can you be just a little more specific and precise than just hand-waving? As above, if it's so obvious, you ought to be able to explain it easily to us. What, exactly, is the difference in applications of probability to all 3 examples? Those examples are 1) exothermic reactions, 2) RM + NS, and 3) lifetime risk of adverse drug effects, to refresh your memory.
Specifically, why do you accept it for 1 and 3, but exclude 2? Please show all your work.
Your retina takes EMR and translates it into a code which is translated by the visual cortex into light, color, and visual images.
You retina takes EMR, in the particular frequencies called "visible light" as a useful shorthand, which has been streaming continuously from the sun for the past 4.6 billion years or so and translates it via sequences of chemical reactions into nerve signals, which are also chemical reactions, which are translated by the visual cortex, using additional nerve signals, which are also chemical reactions, into the appearance of light, color and visual images. Because the particular frequencies called "visible light", with those differences in frequency and intensity that we perceive as color and visual images, already exists external to the eye and brain.
If a tree falls in the woods, there will still be vibrations in the air which can then be perceived as sounds. There is a reality external to the brain, you semantic-mangling sophomoric Platonist.
And as for recommended reading, I'd bet a cookie that you still haven't read this very post, or the one linked to at its start, or you still haven't understood them.
Wazza: In the first sentence you call me stupid and an idiot.
Yeah, Wazza is psychic.
In fact, all of us here are.
We know exactly what stupid shit you're going to say next, but just can't seem to stop ourselves from responding out of a sense of responsibility to any honestly ignorant lurkers out there.
…or you still haven't understood them.
The smart money's on this horse.
The smart money's on this [not understanding the articles, even if he did actually read them] horse.
On April 5, I posed a clinical reasoning question; on April 15, Dr. Steve managed to muster the following detailed technical explication:
Somehow that doesn't reach the level of mutations forming retinas, optic nerves, a visual cortex, eyelids, lenses……………either.
Even granted that he's probably got other things going on in the meantime, I was hoping an erstwhile undergraduate biology major could provide more meaningful scientific content after 10 days than just "Somehow". Again, I am disappointed.
That, combined with:
But if in your mind it does
which is the most incompetently-executed attempt at a double-reverse mind-fuck I've seen in some time, tends to reinforce your assessment.
His failure to comprehend the basic concept of external validation in that attempt, however, does track well with his getting all hung up on the "tree falling in a forest with no one around" puzzle that hung us all up for a little while in 8th grade or so.
Owlmirror: "Because the particular frequencies called "visible light", with those differences in frequency and intensity that we perceive as color and visual images, already exists external to the eye and brain."
SB: Not as color and light, Owlmirror, but as EMR of visible light frequencies. A perceiver (observer) with equipment is required for color, light, and visual images.
Owlmirror: If a tree falls in the woods, there will still be vibrations in the air which can then be perceived as sounds.
SB: Again, by a perceiver (observer) with equipment. No observer with equipment, no sound.
Thalarctos: "……his getting all hung up on the "tree falling in a forest with no one around" puzzle that hung us all up for a little while in 8th grade or so."
SB: Obviously not one of you understand the concept of an equipped observer being required for there to be sound or light (or smell, or taste, or touch). Thalarctos, you are still hung up, and you don't get the gist of the question. I would highly recommend that you get back to the eighth grade and do some serious studying. It really isn't that difficult. I can see why all of you are so pissed off at me and the concept. For M and NS to go from "light sensitive cells" to a full visual system would be impossible, since M and NS would have no idea what the reward would be after going through hundreds of thousands of mutations and jumping that incredible chasm. Another "How did it know." Someday maybe one of you will be sitting somewhere, and you will get a brain flash….and get it. But probably not. Nite.
Thalarctos, you are still hung up, and you don't get the gist of the question. I would highly recommend that you get back to the eighth grade and do some serious studying.
No, you don't get it, and spending anymore time with you on it is a waste. The mixture of pig-ignorance and smarmy condescension is pretty nauseating. It's clear you're interested neither in responding to the specific points people make, nor in learning anything.
It really isn't that difficult. I can see why all of you are so pissed off at me and the concept.
I'm not pissed off at you, so much as I am sad that someone with the opportunities to learn that you have had would squander them for such a hopelessly confused mass of porridge, as it were.
I teach people who work very hard to pull themselves up out of circumstances that prevent them from getting a solid science education. It's never as good when you have to go back later as an adult, having missed out the first time because the resources just weren't there, and yet, they persevere in the face of it. They would never understand why someone as privileged as you have been would choose to throw away that opportunity with both hands. And, frankly, neither do I.
Fortunately, you're not my problem.
For M and NS to go from "light sensitive cells" to a full visual system would be impossible, since M and NS would have no idea what the reward would be after going through hundreds of thousands of mutations and jumping that incredible chasm. Another "How did it know."
And therein lies your cherry picking. You demand that RM and NS must "know" the outcome before they go through it, yet you do not make the same demand on components of an exothermic reaction or on the lifetime risk of pharmacological complications. And when people point out your inconsistency, you tap-dance like Richard Gere in Chicago in an attempt to distract them. (It doesn't work, btw.)
Someday maybe one of you will be sitting somewhere, and you will get a brain flash….and get it. But probably not. Nite.
Oh, we absolutely get what you're doing already.
You know, you'd find a much more receptive niche for your "biology" grifting among marks who'll eat up your "one specie, two species, red specie, blue specie" level of biological sophistication without knowing enough to see that the emperor has no clothes. They'll sit there while you lie, cover up your own gaps and inadequate and confused half-knowledge, and move the goalposts, and they'll eat it up.
Why you spend your time here instead with people who see through your act is inexplicable. But you can babble away all you want. No one here buys your con, but I'm not going to bother responding to you anymore. There are far better things in life to spend time on.
S"SIWOTI"T:
Obviously not one of you understand the concept of an equipped observer being required for there to be sound or light (or smell, or taste, or touch).
Sigh. OK, logic-chopper, let's run with "equipped observer". You're still wrong, because the simplest possible equipped observer is not a human being, or even a simple animal, but is instead the single eukaryotic cell. They can have sensitivity to EMR in the visible frequencies, and therefore can perceive light; they can have sensitivity to vibration, and therefore perceive "sound"; they can have sensitivity to molecules in their vicinity, and therefore can be said to "smell/taste"; they can have sensitivity to other cells in their immediate vicinity, and therefore can be said to touch.
Thus, the eukaryotic cell has everything potentially necessary to evolve colonies which have those same senses in magnified form.
And of course, as you've already conceded, since the offspring of those cells reproducing can and do vary, all that is necessary is for multicellular life to evolve more complex visual systems is for those multicellular colonies which have slightly different and beneficial arrangements of senses to survive and reproduce better than those multicellular colonies that lack those beneficial arrangements.
Evolution. It just works.
OK, you win. Thalarctos , exothermic reactions are a great example of how a complex binocular vision system evolved. Is that the answer you were looking for? And, Owlmirror, I'm sure eukaryotic cells have good colorful visual images. They can probably recognize each other! And they can hear sound just fine. They probably answer to their names. And, I hope someday just one of you will be able to think independently and objectively, instead of accepting the unbelievable dogma that you were taught, and passing it off to your students. And, bye.
Is that the answer you were looking for?
you seem mentally incapable of doing anything but constructing an endless army of strawmen.
pathetic and delusional.
seek treatment.
And, Owlmirror, I'm sure eukaryotic cells have good colorful visual images. They can probably recognize each other! And they can hear sound just fine. They probably answer to their names.
You're a dentist, right? That means you drill people's teeth with a three-quarter-inch drywall bit, right? And you use Hostess Twinkies™ filling on cavities?
And, I hope someday just one of you will be able to think independently and objectively, instead of accepting the unbelievable dogma that you were taught, and passing it off to your students.
I hope someday you'll be able to address just one argument with a tiny little iota of honesty and intelligence.
Say, maybe your problem is too much mercury fumes. I hear tell that stuff can damage your brain, when it accumulates over time.
And, bye.
Don't let your cognitive dissonance hit you on your arse on the way out.