Possible different paths for evolution

[Czcibor]

The question is not purely scientific but involves also huge amount of creative guess (which only shouldn't violate blatantly contemporary scientific knowledge). I think about something like "The future is wild" or some Dawkins' analyses of probability of evolution of different organs from "The Ancestors Tale".

Which different paths were possible for evolution to take and produce different outcomes? Which interesting (cute ;) ) multicellular organism were possible?

I think especially about possibilities for Earth life, though if anyone has idea that would be workable on exoplanet (like organism that is reasonable only in case of ex. tidally locked planet) also feel free. Only to narrow down ideas I suggest first assuming carbon chauvinism.

Animals, plants, whatever... (they don't even have to be eukaryotes)EDIT: Also partial ideas are welcome (not whole organism, but interesting mechanism that could be used)EDIT2: Example of partial idea: evolving from squids that 'fly' after using jet propulsion, for animals that can glide, to finally animals with ability of true flight.

 

[willbell]

I suggest you read "Wonderful Life" by Stephen Jay Gould, he's a masterful author (much better than Dawkins at least), and the book mainly deal with possibly alternative turns and the creatures that could have been the winners.

I'll give you a couple examples:

- Precambrian life - was mostly flat, it was another solution to a basic problem, they solved it by being flat with lots of surface area while we solved it by having depth but having internal organs with a surface area (I forget why that is the way it is, I tried looking it up online). If you are especially creative you could come up with a new solution.

- Cambrian life - the Cambrian explosion saw several hardbodied organisms arise, and while many species died soon, others managed to succeed. Opabinia, Anomalocaris, and Trilobites are all examples that eventually went extinct.

- Permian life - the greatest mass-extinction ever saw 95% of land species extinct. This could have gone differently, and we might still be dominated even more-so by invertebrates. If connected with continued high oxygen levels we could see bigger invertebrates.