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I've never really grasped where the surprise comes from with these kinds of discoveries - we know that our ancestry always had the potential to give rise to lin

I've never really grasped where the surprise comes from with these kinds of discoveries - we know that our ancestry always had the potential to give rise to lines that look very much like us, since we look very much like us. Why should it be a surprise if it happened more than once? We're looking at a terribly long timescale, after all - at least by comparison to our recorded history.

gus_massa 9y ago
Evolution is not linear. At each step there are multiple choices. If you split a population, each one will have different problems in it's environment to solve or they may "find" different solutions to the same problems. After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. [An easy case is when the number of chromosomes changes in one of the part but it doesn't change in the others. But more subtle changes are more frequent.]
- danans 9y ago
  > After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. The time scales being discussed here are orders of magnitude too short to even consider speciation, evidenced by what we know about our human/Neanderthal hybrid ancestors, and the fact that a Pygmy or Khoi-San person can have viable offspring with any person of the opposite gender in the human diaspora today.
has2k1 9y ago
I think how you attribute the surprise matters. The order of discoveries brought forth a conventional story that stood for a seemingly long time. Now that story may need to be re-examined. There is a difference between the discovery & subsequent scientific reports and the story drawn from them. The story is less accurate, tends to be more romantic and gets the widest exposure. Even the scientists subscribe to one version or another because they are human. The likely change in the common story is the source of the surprise and excitement. This process guarantees that there will always be a surprise, and roughly speaking it will be directly proportional to how long the story has been in place and inversely proportional to the number of such competing stories.

gus_massa 9y ago

Evolution is not linear. At each step there are multiple choices. If you split a population, each one will have different problems in it's environment to solve or they may "find" different solutions to the same problems. After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. [An easy case is when the number of chromosomes changes in one of the part but it doesn't change in the others. But more subtle changes are more frequent.]

danans 9y ago
> After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. The time scales being discussed here are orders of magnitude too short to even consider speciation, evidenced by what we know about our human/Neanderthal hybrid ancestors, and the fact that a Pygmy or Khoi-San person can have viable offspring with any person of the opposite gender in the human diaspora today.

has2k1 9y ago

I think how you attribute the surprise matters. The order of discoveries brought forth a conventional story that stood for a seemingly long time. Now that story may need to be re-examined. There is a difference between the discovery & subsequent scientific reports and the story drawn from them. The story is less accurate, tends to be more romantic and gets the widest exposure. Even the scientists subscribe to one version or another because they are human. The likely change in the common story is the source of the surprise and excitement. This process guarantees that there will always be a surprise, and roughly speaking it will be directly proportional to how long the story has been in place and inversely proportional to the number of such competing stories.