TheBear
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The question of whether we, as a species, are still evolving, sometimes inspires visions of a new-and-improved Homo sapiens, complete with super-sized brain, disease-resistance, and the ability to withstand the pollutants and toxins common in a techno-centric future. While science fiction writers have come up with imaginative and entertaining answers to the question of how humans might be evolving, the responses of the scientific community have been more staid. Perhaps, they've suggested, some genes for withstanding epidemic disease are currently on the rise. However, with the improved genetic sequencing technologies that have come online in the last decade, many biologists are now prepared to offer more specific hypotheses as to how species are changing. Recently, a team of researchers led by scientists at the University of Utah announced that they'd scanned the genomes of 270 people and found evidence that humans are not only evolving — but that we've been adapting at an unusually rapid pace — at least on evolutionary timescales. The group has also made the controversial suggestion that human populations on different continents are evolving away from one another. However, a look at the evolutionary biology behind the headlines highlights some limits of this research."Post 143 shows that there isn't nearly enough water on this planet to make global flood possible."
Here is What I found
Geophysically, we begin with a pre-Flood earth differentiated into core, mantle, and crust, with the crust horizontally differentiated into sialic craton and mafic ocean floor. The Flood was initiated as slabs of oceanic floor broke loose and subducted along thousands of kilometers of pre-Flood continental margins. Deformation of the mantle by these slabs raised the temperature and lowered the viscosity of the mantle in the vicinity of the slabs. A resulting thermal runaway of the slabs through the mantle led to meters-per-second mantle convection. Cool oceanic crust which descended to the core/mantle boundary induced rapid reversals of the earth's magnetic field. Large plumes originating near the core/mantle boundary expressed themselves at the surface as fissure eruptions and flood basalts. Flow induced in the mantle also produced rapid extension along linear belts throughout the sea floor and rapid horizontal displacement of continents. Upwelling magma jettisoned steam into the atmosphere causing intense global rain. Rapid emplacement of isostatically lighter mantle material raised the level of the ocean floor, displacing ocean water onto the continents. When virtually all the pre-Flood oceanic floor had been replaced with new, less-dense, less-subductable, oceanic crust, catastrophic plate motion stopped. Subsequent cooling increased the density of the new ocean floor, producing deeper ocean basins and a reservoir for post-Flood oceans.
Where's the evolution?
How do scientists look at the DNA of people alive today and figure out how recently natural selection acted on their ancestors? The answer relies on an evolutionary phenomenon called genetic hitchhiking (or a selective sweep). To understand, imagine that a new advantageous mutation (X) occurs on Chromosome 4, in the middle of gene versions P, Q, and R. In genetic terms, we would say that the mutation and those genes are linked — that is, they are close together on the same chromosome. The new mutation is so beneficial that its carrier leaves lots of offspring — many of whom also carry the mutation and the other linked genes. Over many generations, natural selection increases the frequency of mutation X, and because they are physically attached to X, gene versions P, Q, and R come along for the ride (i.e., "hitchhike" to high frequency). Of course, as X spreads, recombination occasionally occurs between it and its neighboring genes, breaking down this tight association somewhat. We begin to see X in association with different combinations of gene versions (e.g., with r instead of R). If we examine the population at the end of this process of natural selection, we will see mutation X at high frequency, often occurring alongside the same set of gene versions (P, Q, and R), and less frequently alongside other gene versions (p, q, and r).
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