What is Megaevolution?
[[File:Opabinia BW2.jpg| thumb | right | 220px | ''[[Opabinia]]'' made a big contribution to interest in the Cambrian explosion. ]] [[File:Marrella (fossil).png|thumb| 220px| This ''[[Marrella]]'' specimen shows how clear and detailed the [[fossil]]s are from the [[Burgess Shale]] [[lagerstätte]].]] [[File:Ediacaran trace fossil.jpg|thumb|220px|An Ediacaran trace fossil, made when an organism burrowed below a [[microbial mat]].]] [[File:DickinsoniaCostata.jpg|220px|thumb|right|''[[Dickinsonia]]'', an [[Ediacaran]] animal, with a quilted appearance.]] [[File:Olenoides serratus oblique with antennas.jpg|thumb|220px| A fossilized [[trilobite]]. This specimen of ''Olenoides serratus'', from the [[Burgess shale]], preserves 'soft parts'&nbsp;– the antennae and legs. ]] '''Megaevolution''' is a term which describes the most dramatic events in [[evolution]]. By that is not meant a different kind of evolution; rather, it means evolution which produces a tremendous effect. It is not suggested that the evolutionary processes involved are special although, in some cases they might be. Since the word 'macroevolution' can apply to relatively modest changes at the [[species]] and [[genus]] level, 'megaevolution' may be used for really huge changes. The [[adaptive radiation]] of [[birds]] in the [[Lower Cretaceous]], [[teleost]]s in the [[Cretaceous]], [[flowering plants]] in the [[Upper Cretaceous]], [[mammals]] in the [[Eocene]], [[moths]] in the Cretaceous are striking examples of macroevolution. However, there are even more important events in the history of life. An interesting list was prepared by Maynard Smith and Szathmáry, which they called '''the major transitions in evolution'''. They did the list twice.<ref>Maynard Smith J. & Szathmáry E. 1995. ''The major transitions in evolution''. Oxford University Press, p6. {{ISBN|0-19-850294-X}}</ref><ref>Maynard Smith J. & Szathmáry E. 1995. 1999. ''The origins of life: from the birth of life to the origins of language''. Oxford University Press, p6. {{ISBN|0-19-286209-X}