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Human evolution: Why we walk upright – because savannah replaced forests …

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In “Humans originated alongside rivers, evidence suggests” ( MSNBC, December 20, 2011), Charles Choi reports, “Sediment studies dispel woodland, grassland theories at 4.4 million-year-old site in Ethiopia”:

What may be the earliest known ancestor of the human lineage, the 4.4 million-year-old Ardipithecus ramidus, or ” Ardi,” was discovered in Aramis in Ethiopia. The precise nature of its habitat has been hotly debated — its discoverers claim it was a woodland creature far removed from rivers, while others argue it lived in grassy, tree-dotted savannas.

All in all, carbon isotope ratios suggest the environment back then was mostly grassy savanna. However, the way in which those ratios fluctuate suggests riverside forests also cut through this area. Oxygen isotope ratios that are closely linked with climate also suggest the presence of streams, researchers added.

Knowing the context in which our distant relatives dwelt when key traits such as walking upright evolved can shed light as to why such characteristics developed in the first place. For instance, as savannas began dominating what were once primarily forests, it might have made more sense to start walking on two feet to conserve energy when moving through tall grasses.

Hmmm. If  walking upright makes so much sense, why didn’t various wildlife start doing it? Just wondering.

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Nice recent interview of Dr. John Sanford:
Dr. John Sanford Genetic Entropy and the Mystery of the Genome 1/2 http://www.youtube.com/watch?v=pJ-4umGkgos Dr. John Sanford "Genetic Entropy and the Mystery of the Genome" 2/2 http://www.youtube.com/watch?v=K8KbM-xkfVk
This recent chimp-human genome comparison is of interest:
Genome-Wide DNA Alignment Similarity (Identity) for 40,000 Chimpanzee DNA Sequences Queried against the Human Genome is 86–89% - Jeffrey P. Tomkins - December 28, 2011 Concluding staement: Depending on the BLASTN parameter combination, average sequence identity for the thirty separate experiments between human and chimp varied between 86 and 89%. The average chimp query sequence length was 740 bases and depending on the BLASTN parameter combination, average alignment length varied between 121 and 191 bases. Excluding data for the number of clones that did not align or the large amount of bases within clones that did not align, an unbiased conservative estimate of genome-wide human-chimp DNA similarity is not more than 86–89% identical. The conservative nature of these estimates is further noted by the fact that the 40,000 sequence chimp sequences that were tested, represent pre-selected homologous sequence already known to align to the human genome. http://www.answersingenesis.org/articles/arj/v4/n1/blastin
HMMM bornagain77
Evolutionary PhD thesis: Humans started walking upright to free our forelimbs so that we could scratch and wipe our butt and pick our nose. Joe

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