Submitted by 0011000l t3_10jauhb in askscience
for example we have an evolutionary step of A --> B --> C --> D. where D has gone extinct. is there a possibility if the conditions were right the reappearance of D through the evolution of C?
Submitted by 0011000l t3_10jauhb in askscience
for example we have an evolutionary step of A --> B --> C --> D. where D has gone extinct. is there a possibility if the conditions were right the reappearance of D through the evolution of C?
I remember this news article of how a bird "re-evolved" itself. Here It might be similar to what OP said. Though it'll be better to find a scientific article than rely on clickbait news
Not to mention if a species became extinct due to natural forces those would preclude evolving into that form in the first place. That wouldn't necessarily apply to human-caused but they are too recent to know.
This has been observed, it's called iterative evolution or Lazarus taxon or Elvis taxon.
Note the rationale behind renaming Lazarus to Elvis is to allude to impersonators and clarify that it is not actually being reborn. Given how much genetic information there is, superficially "the same" species (such as the "re-evolved Aldabra rail) will still be different genetically.
First, all animals evolve at a similar pace. If you got A->B->C->D, then D got extinct, A, B, C won't exist anymore, so there's no C to evolve back into D.
Second, mutations are random and the number of possibilities is extremely large, enough that we can consider it almost infinite. So the probability to have mutations that bring back the same species that got extinct before is almost 0.
What does happen is convergent evolution in which a species evolve to be morphologically similar to another species (extinct or not) because they occupy a similar ecological niche (what they eat and the environment they live in). Though they are morphologically similar, they'll still be as genetically different as expected for species that diverged when they did. They'll still have a lot of differences due to those genetic differences.
The amount of random chance involved means that it is practically impossible.
Besides that, the course of evolution of one species is influenced by species in the surrounding ecosystem. Symbionts, competitors, parasites, diseases etc. that were present when C evolved to D all have an influence. But those species have also evolved in the mean time. The exact same conditions will never arise again.
It has happened many times. The crab has been evolved into several times throughout history. Rats and mice are not even closely related. Of course, it's not the same exact species each time but similar enough to be considered almost the same to most people.
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People have already answered. I would like to add, see convergent evolution. Same évolutive pressure results in similar response (results). But similar is important not the same. As there never have been 2 deck of cards shuffled identically (given they were well shuffled), you will never get exactly the same thing.
How similar things can be? See barracuda and muskellunge, carcinization to begin with! Thyalcine and canids.
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Evolution doesn’t (and can’t) "retrace its steps". So, almost certainly this would be impossible. It would be like two different rainstorms producing exactly the same raindrops falling in exactly the same places with identical lightening and thunderclaps. Waaaay too many variables for the exact thing to happen twice. Similar (ref convergent evolution), yeah, but not identical.
If selective pressure and genetic diversity support it then evolution proceeds (realizing that actual speciation may also require isolation of a sub-group). However, the underlying premise of a linear process is not how evolution works.
beezlebub33 t1_j5jf1c4 wrote
While it's theoretically possible, it's unlikely.
First, organisms evolve based on mutations and differential reproduction, so you would need the same sorts of mutations and the same sort of selection pressures. Both of these are unlikely, the conditions just are not the same. Also, why did D go extinct? Because they died out because of over competition in their niche, some parasite, etc. ; well, it would affect a new D too. And of course mutations are random, so it's pretty much impossible to exactly replay.
That said, we do have lots of examples of convergent evolution, where different organisms have evolved to fill in niches in different areas. See: https://en.wikipedia.org/wiki/List_of_examples_of_convergent_evolution . Let's say there is a land that doesn't have a large diversity of birds (say, the Galapagos). The first birds that arrive will radiate (diversify through evolution) to fill lots of different niches, such as eating nuts, eating fruits, eating insects, even though they had the same progenitor species. Interestingly, the evolved organisms filling the niche don't do it quite the same way, because evolution adapts what is at hand.