Well I'll Be A Monkey's Uncle

killproc writes "A new report suggests that interbreeding between humans and chimpanzees happened a lot more recently than was previously thought. The report, published in the most recent issue of the journal Nature, estimates that final break between the human and chimpanzee species did not come until 6.3 million years ago at the earliest, and probably less than 5.4 million years ago."

Comments

Key line from TFA

[Daniel Dvorkin]

"The Nature paper joins a wave of work showing that the lines between species are hazy ..."

This is the critical point that creationists who blather on about "macroevolution vs. microevolution" (a distinction without a difference) and "nobody has ever observed a speciation event" (just not true) willfully miss. Species lines are imposed by observers after the fact; they are not inherent in the nature of living organisms.

Re:Key line from TFA

[plunge]

"In all the papers I have read I have yet to see anyone counter Behe's rather simple "irreducable complexity" issues in way that I could go, "Oh, okay. That makes sense." Instead, most of the counter arguments are as poor and emotionally charged as those of creationists defedning a literal interpretation of Genesis."

Of course, it's easy to characterize them that way, without actually stating any of the problems with them.

"The fascinating machines that biological organisms are just do not compute to me as a product of chaos or random placement."

It sounds like that's because you've bought into the remarkably poor analougy Behe uses in calling them "machines" in the first place.

It's interesting: if you read Behe, it sounds as if the flagella, for instance, is some remarkable single structure which only works in exactly one way: an island of function in a sea. But of course, once you look into the matter more, you find that there are many many different types of flagella with all sorts of variations of structure... and even things which have some of the same structures of flagella, but play different roles.

Once you start finding things like this, Behe's picture of things starts to fall to pieces.

"I also grow tired of the sheer arrogance of the evolution camp who appear to believe as humans that our "science" has moved to the point of infallibility."

Again, this is an accusation that's easy to make, not a fact. I've NEVER met a scientist who believed that their knowledge was complete or infaliable. In fact, scientists are probably better than ANYONE ELSE in the way they are very specific about what the evidence can and cannot tell you about something.

I think what you are mischaracterizing is not them claiming to be infaliable, but them objecting to critics who are plain dishonest about how science works or what the evidence is.

"It's the very questioning of the status quo and accepted theory that continues to allow us to advance our knowledge."

And that's the greatest irony of all. No one is questioning things more rigorously than scientists: any number of vast revisions and innovations within science have happened over just the last few decades.

Creationists and ID proponents on the other hand, are the ones repeating the same darn arguments over and over, completely immune to arguments and evidence contradicting their views. They are the ones who insist that they need not actually learn about what evolution says or what the evidence is before declaring it bunk: and when told that this is ignorant, they scream and whine. But guess what: spouting off about something you haven't bothered to understand IS ignorant.

Misleading

[Reckless Visionary]

What this shows is that there was likely interbreeding between the ancestor line of humans and the ancestor line of chimpanzees. Unfortunately, all the headlines I've read skip that distinction and dive right into "humans and chimps interbred." They were not either modern humans or modern champanzees, and were likely much closer in genetics and appearance than we are to modern chimps, even though even now we are very close genetically after 5 million years of divergence.

Re:There won't be any controversy here!

[Whiney Mac Fanboy]

That being said, I don't think we descended from chimps. I've made a rather lengthy arguement about this before and I'm not sure I totally want to get into again, but I just don't believe humans came from chimps.

Dude, nobody thinks humans are descended from chimps. Chimps and Humans have a common ancestor (and now the divergence line is a little more blurred).

Misleading

[Shihar]

I hate to quibble, but the summary is not quite right. It isn't like there were chimpanzees, humans evolved "up" from chimpanzees, and the chimpanzees remained the same. This isn't how evolution works. What happened was that a single species broke into two separate species. Both species continued to change and evolve. A chimpanzee has done just as much "evolving" as a human has, it just went in a different direction. Whatever the case though, if you were to compare a chimpanzee ancestor to a human and a modern chimp, you would find that you are looking at three very different species.

I am not saying that human evolution isn't teh pwn, but keep in mind that things don't "branch" like in a tree where the original branch remains. When things branch they move off in different directions and the original species before the branch is lost.

Re:There won't be any controversy here!

[pe1rxq]

You mistake in the way you think about selection.

There is no 'law of evolution' kind of thing that says that a species will involve into something more complex or intelligent.
Natural selection simply works because a certain species is capable to stay in existence.
Sometimes being stupid and just breed is more efficient than being intelligent.
Ants have a complex structure which allows them to spread very efficiently. Knowing how to paint for some reason wasn't needed for them to spread widely and thus such an feature would only result in extra lugage to carry around.
Maybe out species at some point managed to stay alive longer by being a little bit more creative than our cousins. That might have been an factor that resulted in more offspring.

Jeroen

Re:There won't be any controversy here!

[Anonymous Coward]

Abstraction is a strong part of the process used in learning. View a set of data, create an abstract theory. Humans happen to be better at it than most animals.

Art is simply one way of expressing these abstractions. Same thing with God - you see a bunch of seemingly miraculous things happening... something must be acting to cause those miracles. Ergo, God.

As to ants vs. humans, well, ants don't have the same needs we do because all ants are moderately simple. They just don't have the neuron mass to act independently. Nor is it likely for them to evolve the neuron mass, because of structural issues re: exoskeletons.

Re:There won't be any controversy here!

[gowen]

why the need for art and culture

What makes you think there's a need for art and culture? Humans didn't evolve a desire art anymore than kittens evolved an enjoyment of playing with wool. It's the vestige, an accidental by-product, of some things we did find evolutionarily advantageous : intelligence, language, society and imagination.

Re:Hold it a second!

[espressojim]

Well, as a bioinformaticist who has been following this work for a while (both the first and last authors, along with most of the others present at our weekly group meeting), I'd say that the work isn't sloppy.

It is controversial, as it doesn't match with the fossil record. But if you knew the guys involved (and the internal vetting process at the Broad), you'd understand that this work has gone through massive peer review by some of the most gifted individuals in genetics I've seen.

I'd guess that John Hawks isn't a genetics specialist (Just as David isn't an anthropologist), so when data starts conflicting, it's hard for anyone to give ground. I think it's exciting, because it allows for more experiments to be divised on both ends, and for more clarification to be arrived.

In other words, the scientific process.

Re:There won't be any controversy here!

[mrpeebles]

Just to agree with you, and add a little bit: in general, science doesn't need to explain the entire story. In fact, science has a long history of concentrating on the things it can explain, and ignoring the things that it cannot. For example, when Newton's law of gravity came out, there was a lot of controversy as to how objects could interact with each other at a distance, about which Newton's law of gravity says nothing. But how can you argue with it? It is so powerful, and so elegant, it must be getting part of the story right, so to speak. It wasn't until 200 years later, with Einstein, that physics had anything interesting to say about how those objects interacted with each other at a distance. Similarly, there seem to be a lot of big, important questions left in the evolution of the human species. It does seem quite little strange to understand evolutionary pressures that allowed us to carry food on the savannas also allowing us to go to the moon, or paint the Mona Lisa. Maybe there is more to the story then. But that doesn't need to mean that the part of the story we do have is wrong.

Re:There won't be any controversy here!

[SatanicPuppy]

The point is specialization. Humans, for whatever reason, specialized in tool use as a means for survival. We learned to see the environment as something to be manipulated. Abstract thought became an advantage, so it prospered in our evolution, and we adapted to it. Art is an outgrowth of abstract thought and tool use. Doesn't serve any purpose really, it just happens to be a side-effect of the kind of brain that could produce gunpowder.

Ants, on the other hand, are pretty near perfect. They are utterly dominant in their niche, amazingly successful. The ongoing ant-ian evolution involves coming up with new and exciting ways to be dominant in their niche. Better venom, better reproductive turnaround, better coordination, ability to survive in other environments. The ability to create art is hilariously useless to them. Advanced cognition is hilariously useless. Can you imagine the worker ants going on strick because they don't get enough nectar, or get sent into too many hazardous situations? Any ant that started evolving in that direction would be less fit to live, an evolutionary flop.

Intelligence is not the end-all be-all in evolution. Why are chimps not intelligent artisans like us? Maybe because they climb trees better than we do. Why not? They didn't need to pick up tool use, because they could out-climb all their predators, whereas we had to have a big ass club up in the tree with us because panthers could climb better.

Re:Hold it a second!

[Wabin]

Ugh. As a genetecist whose lab does work on this stuff (I personally avoid human data, but do work on speciation), I would say that one of the good points Hawks makes is that there is a lot of work that should have been cited that wasn't. They present their paper as if they are the first to suggest that there was a period of human-chimp hybridization. I won't go into the older literature, some of which they do cite, but more recently, Navarro and Barton (2003) (link may be behind paywall, sorry) provided some evidence for extensive hybridization. Also, Osada and Wu (2005) (which is cited, but really really strangely) were more explicit in their claim of hybridization (though here they refer to it as disproof of pure allopatry (a rapid event driven by geographic isolation)). Some of the methods in the "new" paper appear to be directly derived from tests in Osada and Wu. The work itself is good, but maybe not as groundbreaking as they would like to believe. Personally, I was just waiting for a good data set to come up with better evidence for something I was quite confident of already. This does that.

I also happen to think that as we investigate more and more pairs of close species, we will find this is not at all an uncommon pattern. There are lots of hybrids out there in nature, and you can be sure that genes make it across "species boundaries" with some regularity for quite a while.

One final note to destroy my credibility. Is anyone surpised that people had sex with chimps? (Okay, proto-humans with proto-chimps) We are a couple of horny species. I don't know too much about chimp sexual habits, but we humans sure are a kinky bunch to boot.

Re:There won't be any controversy here!

[plunge]

Ok, well, then the answer is simple: they're lying.

First of all, by all respects, positive mutations in practice DO happen, and indeed one can point to any number of recent examples just in humans, just recently. Tetrachromaticism in women is recent. So is the immunity to the negative effects of LDH cholesterol developed in a single man in Italy (creating descendants among whom heart disease and strokes are vanishingly shockingly rare).

Second of all, think about it logically. Mutation is random. That means that anything it can do, it can undo. So if it can have bad effects, then it can also have good effects (for instance, if one mutation breaks something by changing a T to an A, then the next mutation can change the A back to a T, thus having a positive effect).

Thirdly, creationists generally also admit that mutations can cause observeable variations in a species: longer beaks, shorter legs, etc. But any of these can have positive effects, so they've just unknowingly admitted to something they elsewhere deny.

Finally, talking about mutation and function in this way is itself misinformed. Whether or not a mutation is "beneficial" or not depends a great deal on context. A particular mutation can have a negative effect in one context, and a positive effect in another one. There are certainly mutations that very clearly are better or worse than what came before in all contexts, but by and large there is no objective measure of whether a mutation is beneficial, neutral, or positive. It all depends on a lot of other factors and how it plays out.