Evolution, Selection, Silver Foxes and Adrenaline

Reply Mon 2 Aug, 2010 07:49 am
Thomas wrote:
Dawkins concludes with a picture that still makes me smile: "Is lactose tolerance just the tip of the iceberg? Are our genomes riddled with evidence of domestication affecting not just our biochemistry but our minds? Like Belyaev's domesticated foxes, and like the domesticated wolves that we call dogs, have we become tamer, more loveable, with the human equivalents of floppy ears, soppy faces, and wagging tails? I leave you with the thought, and move hastily on."

It's an interesting idea. But to explore it I think we need to work from a more accurate idea of what "tameness" actually means in this case.

Tameness in this case might be more precisely defined as the ability to interact with others, either cross-species or inter-species. In which case all we might be observing is that it's evolutionary advantageous to exploit interactions with groups rather than to exist in isolation. And that might be an expected underlying result of being a mammal (since mammals necessarily need to wean their offspring and protect them until maturity). It might also apply to birds, but would be less necessary in reptiles (or any organism that doesn't need to actively support its offspring).

Reply Mon 2 Aug, 2010 11:45 am
According to DAwkins, as an adaptation, the lowering of the animals safety one, or that distance that an animal leaves open between it and a possible threat, had been reduced after several generations and all but disappeared after 20 generations, until, after 30 generations, 70% of offspring were "huggeable". The allele locii that amassed adrenaline production and (later) allowed for "neotony" (cutesy looking ,floppy ears, piebald coat, shortened snout) were all decreases in "flight or fight " responses .
Sveral alleles but one selector gene.
Reply Mon 2 Aug, 2010 12:08 pm
I guess the advantages to group stabilization out-select the need for fight-or-flight response in some situations. This might also indicate that mammals near the top of the food chain are more likely to be selected for "tameness" than those at the bottom of the food chain.
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Reply Fri 19 Nov, 2010 12:02 am
Nove did a whole show called Dogs Decoded about this. It was very interesting. They found that when you have two cups with one having a morsel of food under it and a human points to the one with the food, the dogs went immediately for the one the human pointed to. Neither the wolves or the chimps did. The foxes that were chosen for lower adrenaline levels also had very obvious physical changes as well as behavioral changes, as did the wolves. This made me think, what would happen if we selected chimps for lower adrenaline levels and mated them. Would they show more socialized behavior like the foxes and the wolves and would they also start showing physical mutations as well? It hasn't been done yet, but I wonder if they would start growing longer legs and shorter arms and larger skulls and smaller jaws and teeth ? If that would happen I think that we would have very conclusive proof of evolution.
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Reply Fri 19 Nov, 2010 12:41 am
Check this out




This is an excerpt from the Nova program titled, " Dogs Decoded ". The full transcript is available at the web site below.


NARRATOR: So how does the intelligence of a dog compare in the animal kingdom? New research is discovering that, in certain ways, dogs may actually think more like us than any other animal, including our nearest relative, the chimpanzee.

JULIANE KAMINSKI: Of all the questions around the evolution of human cognition, of course people would focus in on chimps, quite naturally, and suddenly there were dogs doing something that not even chimps could do.

NARRATOR: Cognitive psychologist Juliane Kaminski compares chimps with dogs, in a series of revealing experiments. At Leipzig Zoo, Kaminski is testing chimps to see if they can understand human gestures, like pointing, to find a hidden treat.

As simple as it seems to us, even our nearest primate relatives fail the task miserably.

JULIANE KAMINSKI: She's not really focusing on me, and she's simply making her own choice. Most of the time, you can see that she makes a decision, long before I give my gesture. She doesn't even wait for my information.

It's such an uncooperative interaction, so it's like really I'm providing information for her to find food, which is just simply something which would never happen in a chimp group, really. I mean a chimp wouldn't go, like, "Oh, look, there's the banana." And then another chimp could go and get it.

NARRATOR: Since we're the only species that makes this gesture, it would be remarkable if any animal could understand it. But dog owners take it for granted that their dogs respond to pointing.


NARRATOR: For Kaminski, it's proof of their extraordinary social intelligence.

JULIANE KAMINSKI: If you really look at that gesture, it's an informative gesture. So it's, in its essence, a very cooperative interaction, so, I'm really helping you to find something. And for dogs, following, pointing seems to be very natural, and it makes dogs extremely interesting.

NARRATOR: In fact, dogs are so tuned in to our social cues, they can even pick up on something as subtle as the direction of our gaze.

Humans have unique almond-shaped eyes with exposed white sclera visible on each side.

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