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30,000 is an evolutionary eternity. The huge variety of bizarre dog breeds was created over a few centuries. Foxes were turned from nigh untameable wild animals

30,000 is an evolutionary eternity. The huge variety of bizarre dog breeds was created over a few centuries. Foxes were turned from nigh untameable wild animals into pets in a few decades.

jessriedel 14y ago
That's not evolution, that's selective breeding by humans.
- agildehaus 14y ago
  Selection is a component of evolution. Human selection is just one type of it, natural being the other. Wolves did evolve into dogs, but not naturally by our definition of "natural".
btilly 14y ago
Yes, 10,000 years is a long enough time to create a whole new species under normal circumstances. Under the forced breeding that people do, it goes even faster. But normally a species is pretty well adapted to its environment and does not have trivially obvious improvements to make, and therefore changes slowly. Therefore the the average mammalian species manages to survive mostly unchanged for about a million years or so (figure shamelessly stolen from http://en.wikipedia.org/wiki/Background_extinction_rate http://en.wikipedia.org/wiki/Background_extinction_rate - and they cite a 1993 study for it). Thus one would expect, on average, that 97% of the mammalian species that were around 30,000 years ago that to still be around and recognizably be the same kind of animal. This is not actually so, and the main reasons are extinction events caused by people, and the effects of domestic breeding on chickens, dogs, carrots, tomatoes, and so on. But outside of types of things created by humans, there aren't a whole lot of new species running around that didn't exist in pretty close to their current form 30,000 years ago. For example there is likely less genetic difference between you and our ancestors 30,000 years ago than there is between you and an Australian aborigine.
lobster_johnson 14y ago
It's not an "eternity" by any means, but it's enough for selection to take place. Humans are thought to have developed lactose tolerance within the last 10k years, for example (probably closer to 6k, if I remember correctly). In other observed cases, significant selection occured in just a few decades [1]. [1] http://news.nationalgeographic.com/news/2006/07/060714-evolution.html http://news.nationalgeographic.com/news/2006/07/060714-evolu...

30,000 is an evolutionary eternity. The huge variety of bizarre dog breeds was created over a few centuries. Foxes were turned from nigh untameable wild animals into pets in a few decades.

jessriedel 14y ago

That's not evolution, that's selective breeding by humans.

agildehaus 14y ago
Selection is a component of evolution. Human selection is just one type of it, natural being the other. Wolves did evolve into dogs, but not naturally by our definition of "natural".

btilly 14y ago

Yes, 10,000 years is a long enough time to create a whole new species under normal circumstances. Under the forced breeding that people do, it goes even faster. But normally a species is pretty well adapted to its environment and does not have trivially obvious improvements to make, and therefore changes slowly. Therefore the the average mammalian species manages to survive mostly unchanged for about a million years or so (figure shamelessly stolen from http://en.wikipedia.org/wiki/Background_extinction_rate http://en.wikipedia.org/wiki/Background_extinction_rate - and they cite a 1993 study for it). Thus one would expect, on average, that 97% of the mammalian species that were around 30,000 years ago that to still be around and recognizably be the same kind of animal. This is not actually so, and the main reasons are extinction events caused by people, and the effects of domestic breeding on chickens, dogs, carrots, tomatoes, and so on. But outside of types of things created by humans, there aren't a whole lot of new species running around that didn't exist in pretty close to their current form 30,000 years ago. For example there is likely less genetic difference between you and our ancestors 30,000 years ago than there is between you and an Australian aborigine.

lobster_johnson 14y ago

It's not an "eternity" by any means, but it's enough for selection to take place. Humans are thought to have developed lactose tolerance within the last 10k years, for example (probably closer to 6k, if I remember correctly). In other observed cases, significant selection occured in just a few decades [1]. [1] http://news.nationalgeographic.com/news/2006/07/060714-evolution.html http://news.nationalgeographic.com/news/2006/07/060714-evolu...