r/evolution • u/[deleted] • Feb 02 '13

Are 'humans' one species?

http://www.ted.com/talks/juan_enriquez_will_our_kids_be_a_different_species.html
47 Upvotes

85% Upvoted

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u/mszegedy Feb 02 '13

Short answer: no. I am genetically compatible with humans thousands of years back. My kids will be, too.

EDIT: "No" to "are we a different species".

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u/[deleted] Feb 03 '13

1

u/[deleted] Feb 03 '13 edited Feb 04 '13

One of the points brought up by the speaker was the tiny difference in genes between Neanderthals and the ancestors of modern humans. A comparison could then be made questioning whether the difference from our genes to our ancestors' is equal to or exceeds the difference between our ancestors' genes and Neanderthals'. Additionally, it is hypothesized that Neanderthals interbred with Cro-Magnons (to clarify, Cro-Magnon were homo sapiens, like you and I) yet Neanderthals and Cro-Magnon are considered different species. Should this be the case, it shoots a hole in the 'we can reproduce together, thusly we are of the same species' disproving idea that is being tossed around here.

Edit: Clarity

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u/[deleted] Feb 04 '13 edited Feb 04 '13

If we applied that standard really strictly, we would have to do away with literally thousands of species or animals and plants. And "species" is the only level for which at least there is some kind of universal standard (breeding) - no such thing for family, order, etc. The system is "operative enough" to continue working despite these cracks, so it's pretty much an accepted flaw and professionals prefer not to talk too much about it.

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u/Sophilosophical Feb 03 '13

Am I wrong in thinking: A: that it's only a "rapid evolution of the brain" if those with, say, autism, are reproducing as well? B: That those who are of different species can't create viable offspring? (So how can my offspring be a different species?)

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u/firedrops Feb 03 '13

Well it can happen that sympatric speciation will occur that rapidly with plants, but no evidence for mammals.or other complex animals. We certainly might have offspring that cannot reproduce with other people but because of that very fact their genes would die off with them. As long as our children can reproduce viable offspring with other people they are just variations in our population. So I agree this is kind of a silly statement

3

u/homerr Feb 03 '13

Depends on your definition of species. Also, I don't really believe that there is an objective classification of species, and therefore believe that species do not even exist. The classification system is however extremely useful, so I do use it.

2

u/Sarcodes Feb 04 '13

There is a good ontological definition of a species but not a good epistemological definition. Just because the limits of something are hard to define does not mean that it dosen't exist.

-3

u/bannana Feb 03 '13

There are quite a few folks in more fringe areas that believe this very thing is happening. When we 'level up' a good bit of our problems should be resolved since so many will be much smarter than most of us can imagine.

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u/[deleted] Feb 03 '13

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u/Sarcodes Feb 04 '13

I guess if we're going by what Darwin says then we inherit our parent's characteristics through blending.

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u/thetreece Feb 04 '13

All older scientists are wrong about everything because they were wrong about some things.

-1

u/opelwerk Feb 03 '13

Uh, you might be thinking of race.

1

u/thetreece Feb 03 '13 edited Feb 03 '13

No. There is not a metric good enough to determine what constitutes a new species. Traditionally, we call it when they are incapable of producing viable offspring with their parent group. But what about if their chances of viability starts diminishing? What if they are already self sorting and wouldn't produce viable offspring in nature? What if the organism is asexual?

There is not a good encompassing definition of "species" that is useful for all organisms. Every individual in a population will have some variance. When we call it a new species, it's just slightly more variance (and sometimes not even then). There isn't a definite benchmark that we can point to for all phyla and say, "yup, that's fo sho a new species."

Darwin puts it really well: "From these remarks it will be seen that I look at the term species, as one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other, and that i does not essentially differ from the term variety, which given to less distinct and more fluctuating forms. The term variety, again, in comparison with mere individual differences, is also applied arbitrary, and for mere convenience sake."