Biologists observe speciation in butterflies
While I wouldn’t exactly call recent observations “unlocking evolution’s secret,” they do offer some interesting insight into speciation in action. Speciation, of course, is when one species diverges into two, usually because of geographic isolation.
Recent observations, however, have keenly shown that geographic barriers need not exist. And in fact may be a sort of barrier to speciation, particularly with one species of butterfly, Agrodiaetus.
In the case of Agrodiaetus, the butterflies with geographic boundaries tended to show no evidence of speciation, whereas those without boundaries tended to show speciation, which flies in the face of conventional thought. In this case, butterflies with no boundaries living in close proximity to one another tended to breed with those that looked like themselves, thereby having offspring that also had similar markings. But butterflies with geographic boundaries showed no special attraction to mates that looked like themselves.
More interestingly, it has been found that if a rogue member of the butterflies coming from the more isolated genetic pool mated with a butterfly that looked different from itself, produced less viable offspring than those that chose to mate with genetically-similar butterflies. That is, if those butterflies with no geographic boundaries chose to procreate with dissimilar mates, their offspring were less likely to survive. This further suggests a slow divergence of the Agrodiaetus species: natural selection is lending a helping hand.
I think a simple explanation exists: when there are many potential mates around, creatures tend to be more choosey, and this is slowly causing speciation among these butterflies. Picking mates that look similar occurs frequently in the human world as well.
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[...] Brain size also figures into this assertion, because halving the size of a human would theoretically cut brain size by only 15%. A normal human has a brain size of approximately 990cc. So a “hobbit” should have a brain that’s about 750cc. Instead, it was only 400cc — which means that the brain-size corresponds to a creature roughly the size of a meerkat. Of course, geographical isolation is often the cause of evolutionary divergence, so seeing an abnormality like this in an isolated group wouldn’t be entirely surprising. Corroborating the brain-size issue, a skull with a brain matching floresiensis’s size has been found in the vaults of London’s Royal College of Surgeons. That person had microencephaly. [...]
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