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The separation indeed occurred long ago, and the most dramatic evolutionary changes happened then. But the populations on the Galapagos continue to make observa
by helveticaman 18y ago
The separation indeed occurred long ago, and the most dramatic evolutionary changes happened then. But the populations on the Galapagos continue to make observable evolutionary changes because of weather conditions.
http://www.nwf.org/nationalwildlife/article.cfm?issueID=115&articleID=1472 http://www.nwf.org/nationalwildlife/article.cfm?issueID=115&...:
"Recently, the Grants witnessed another form of natural selection acting on the medium ground finch: competition from bigger, stronger cousins. In 1982, a third finch, the large ground finch, came to live on Daphne Major. The stout bills of these birds resemble the business end of a crescent wrench. Their arrival was the first such colonization recorded on the Galápagos in nearly a century of scientific observation. 'We realized,' Peter Grant says, 'we had a very unusual and potentially important event to follow.' For 20 years, the large ground finch coexisted with the medium ground finch, which shared the supply of large seeds with its bigger-billed relative. Then, in 2002 and 2003, another drought struck. None of the birds nested that year, and many died out. Medium ground finches with large bills, crowded out of feeding areas by the more powerful large ground finches, were hit particularly hard.
When wetter weather returned in 2004, and the finches nested again, the new generation of the medium ground finch was dominated by smaller birds with smaller bills, able to survive on smaller seeds. This situation, says Peter Grant, marked the first time that biologists have been able to follow the complete process of an evolutionary change due to competition between species and the strongest response to natural selection that he had seen in 33 years of tracking Galápagos finches."
I'm also aware of the negative correlation between IQ and Fertility; however, this is not without explanation. IQ correlates with k-strategy (bigger investments in fewer children that are slow to develop), and k-strategy correlates with having few children. [1] R-strategists have lower IQs and higher fertility rates. In the society outlined by Gregory Clark in his paper, wealth correlated with reproductive success. Right now, we live in an anomalous situation where food is not a limiting factor. But this is coming to an end; food prices have increased dramatically in recent years, with no sign of falling any time soon. This phenomenon is not new, and illustrates the possible advantages of r-selection.
From Clark's article:
"The strength of the selection process through survival of the
richest also seems to have varied depending on the circumstances
of settled agrarian societies. Thus in the frontier conditions of
New France (Quebec) in the seventeenth century where land was
abundant, population densities low, and wages extremely high the
group that reproduced most successfully was the poorest and the
most illiterate."
http://www.econ.ucdavis.edu/faculty/gclark/papers/Capitalism%20Genes.pdf http://www.econ.ucdavis.edu/faculty/gclark/papers/Capitalism...
[1] http://en.wikipedia.org/wiki/K-selection http://en.wikipedia.org/wiki/K-selection