11–20 of 142 posts
The concept of species is a construct of language.
To me this is the gist of the article as well of the stream of recent discoveries and papers released. It's also a pattern that permeates computer science nowadays, applying to different realms, from system design to DevOps to team collaboration.
Why does it have to be only one ancestor ape, and not several that evolved human-like features simultaneously in the same environment? We have Neanderthal DNA, that we inherited through interbreeding. Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario? Sometimes I think scientists fall for the same simplistic patter…
It doesn’t. That is the crux of this article and almost all the scholarship I’ve encountered on the question over the past few decades.
> Isn't this the most likely scenario?
No. The human genome is unusually homogenous, in part thanks to recent Ice Ages inducing bottlenecks. The simplest explanation, to our proximate evolution, is linear. (The simplest explanation is wrong.)
The fossil evidence, for that matter, while it shows significant overlap, does, broadly, present a remarkably-linear path over about 4 million years, with a series of branching-then-consolidating phases.
Why does it have to be only one ancestor ape, and not several that evolved human-like features simultaneously in the same environment? We have Neanderthal DNA, that we inherited through interbreeding. Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario? Sometimes I think scientists fall for the same simplistic patter…
Such a group would simply be one species. Having many different species as ancestors also wouldn't explain the exceptional homogeneity of the human genome.
The present discovery though doesn't change things as much as the article tries to imply. It just means the speciation (from the appearance of A. afarensis to the disappearance of A. anamensis) lasted longer than previously thought, or at least that the A. afarensis species appeared earlier than we thought.
All the rest is complete speculation and the discovery doesn't really give any reason to think our ancestry tree might be different than previously thought.
Why does it have to be only one ancestor ape, and not several that evolved human-like features simultaneously in the same environment? We have Neanderthal DNA, that we inherited through interbreeding. Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario? Sometimes I think scientists fall for the same simplistic patter…
They have first to geographically split to live and evolve in two separate similar environments and then merge while still being compatible.
This seems to be the rule, rather than the other exception, at least in human evolution. Erectus overlapped with more modern archaics, for example. Habilis overlapped with afarensis.
A lot of these are more about the semantics than the substance. Words like "species" get tricky, when you're dealing with chronspecies, introgression and such.
In any case, our evolution since speciating from chimps is extremely bushy. There are lots of species, and several families. The process involved lots of innovation/speciation and extinctions. Ie, The australopithecine family that this species may have founded produced many species, including at least two that formed their own families with multiple species of their own (paranthropous & homo).
I think this is characteristic of fast evolutionary processes.
The concept of species is a construct of language.
What's the point?
Why does it have to be only one ancestor ape, and not several that evolved human-like features simultaneously in the same environment? We have Neanderthal DNA, that we inherited through interbreeding. Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario? Sometimes I think scientists fall for the same simplistic patter…
Sometimes I think that BBC articles don't do a perfect job of precisely explaining the patterns of thinking of scientists.
The impression I got from a recent PBS Eons video on the non-existing missing link[0] is that interbreeding happened all the time and that a very realistic possibility for the answer is "most, possibly all of them" . [0] https://www.youtube.com/watch?v=pwW40Dj5Sro
Homo habilis started its career as an australapithicine, and could probably reproduce with "non-homo" species.
A lot of the classification only makes sense after the fact. If habilis hadn't produced the homo genus, it would just be an australapithicine, and we wouldn't consider it separate from them.
Why does it have to be only one ancestor ape, and not several that evolved human-like features simultaneously in the same environment? We have Neanderthal DNA, that we inherited through interbreeding. Why can't both we and the Neanderthals be descendent from a varied group of very similar apes that interbred as well? Isn't this the most likely scenario? Sometimes I think scientists fall for the same simplistic patter…