Could a world exist without autotrophs, but have heterotrophs?
I was watching Biblaridian’s biosphere videos and he said it is believed that heterotrophs evolved before autotrophs.
This gave me a cool idea: what if a (my) world had heterotrophs, but no autotrophs? Could the nutrients that original heterotrophs used in the ocean be enough to support an ecosystem on land, or would some sort of autotroph be necessary in order to get enough nutrients for movement?
Edit: someone asked me to clarify my question further, so here I am to answer you questions about my questions! First off- the video is called “Alien Biosperes Part 2” by of course Biblaridian. The time stamp is about 1:08, in which he basically says that “in the history of earth, the earliest organisms were most likely heterotrophic- meaning they were incapable of producing their own energy, and thus had to eat things“ While not said in the video, these heterotrophs (I believe) were throught to get their nutrients from chemicals in the ocean that came out of vents. Ignore the wording of that, as I’m sure it is not 100% spot on. But that is the general idea of it, heterotrophs in the ocean got nutrients from chemicals in vents (and later evolved and broke into autotrophs and heterotrophs.) As for where the heterotrophs would get the nutrients from once moving on to land, well... I’m not exactly sure. Perhaps there are smaller heterotrophs in the ocean that use this method of getting nutrients- that is, eating a sort of “chemical soup”. Then, the food chain could do the rest. 344
“Fish” eat these smaller heterotrophs, something else eats those “fish” and so on. The problem then would be land dwelling animals. Maybe the land dwellers eat sea animals, then other animals eat them. This would mean the whole ecosystem is heavily dependent on sea life. The idea of the whole ecosystem, on land and sea, all being intertwined and interdependent does sound very intriguing though. I fear I have jumped down into a deeper rabbit hole trying to explain this. I hope this helps explain more though! 445