tag:blogger.com,1999:blog-13439734.post1554143163698621838..comments2023-09-03T06:41:01.993-07:00Comments on BLOG OF SCIENCE!: Carnival of Science!Dan Levitishttp://www.blogger.com/profile/13581109290998307861noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-13439734.post-75169712766748112752009-02-09T16:50:00.000-08:002009-02-09T16:50:00.000-08:00The issue isn't that all the evolution that lead t...The issue isn't that all the evolution that lead to rainforest diverstiy happened in the last 20K years, but rather that much of the local kilometer to kilometer diversity happened that recently. This refugia process actually helps to explain why we see all that local diversity. As long as there is continuous habitat, it is hard for populations to become isolated enough from each other genetically for speciation to occur. When a climate shift divides the forest into lots of little pockets, the population in each of them is likely to be isolated from the others, and free to become genetically distinct. If they become genetically distinct enough, then when the climate shifts back and the forest becomes one again, you might end up with a whole group of closely related species, each in its own part of the forest and all gradually spreading into each other's parts.Dan Levitishttps://www.blogger.com/profile/13581109290998307861noreply@blogger.comtag:blogger.com,1999:blog-13439734.post-66598575159291399612009-02-09T12:25:00.000-08:002009-02-09T12:25:00.000-08:00Mostly I find it shocking that 20K years is enough...Mostly I find it shocking that 20K years is enough time to see as much evolution as is evident in the rainforest. You see things talking about species of insect or fungus or what have you that are native to a mere 1 km^2 or some such. I know the definition of "species" is less than ironclad precise, but still. That's a boat load of evolutionary change in what seems like a short span of time. Isn't the whole issue of people failing to accept evolution that they can't grasp the time scales involved? 20k years is not beyond grasp, I don't think. Except I'm not grasping it!jtehttps://www.blogger.com/profile/17318378188704219078noreply@blogger.com