Animal Intelligence and the Evolution of the Human Mind
From Scientific American
The human brain lacks conspicuous characteristics—such as relative or absolute size—that might account for humans’ superior intellect.
Researchers have found some clues to humanity’s aptitude on a smaller scale, such as more neurons in our brain’s outermost layer.
Human intelligence may be best likened to an upgrade of the cognitive capacities of nonhuman primates rather than an exceptionally advanced form of cognition.
Of course, intelligence must emerge from the workings of the three-pound mass of wetware packed inside our skulls. Thus, researchers have tried to identify unique features of the human brain that could account for our superior intellectual abilities. But, anatomically, the human brain is very similar to that of other primates because humans and chimpanzees share an ancestor that walked the earth less than seven million years ago.
As far as we know, no dog can compose music, no dolphin can speak in rhymes, and no parrot can solve equations with two unknowns. Only humans can perform such intellectual feats, presumably because we are smarter than all other animal species—at least by our own definition of intelligence.
The incredible journey taken by our genes
Sixty thousand years ago, a small group of African men and women took to the Red Sea in tiny boats and crossed the Mandab Strait to Asia. Their journey - of less than 20 miles - marked the moment Homo sapiens left its home continent.
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After emerging into the Arabian peninsula, some of our ancestors took sea routes along the south Asian coast to reach Australia 50,000 years ago. Only later, about 40,000 years ago, did we enter Europe - its cold and its Neanderthals making it far less hospitable - while one group of Asians headed farther east over the land bridge that then connected their continent to America.
'We can also see that just before humans left Africa, about 70,000 years ago, mankind was brought to the brink of extinction when Mount Toba, in Sumatra, erupted,' said Wells. 'It was the most powerful volcanic eruption for two million years and dropped thick ash and killed vegetation across the globe. Our research now shows Homo sapiens numbers dropped alarmingly at this time and we only just hung on as a species.'
From The Guardian
Upright Walking Began 6 Million Years Ago, Thigh Bone Comparison Suggests
A shape comparison of the most complete fossil femur (thigh bone) of one of the earliest known pre-humans, or hominins, with the femora of living apes, modern humans and other fossils, indicates the earliest form of bipedalism occurred at least six million years ago and persisted for at least four million years. William Jungers, Ph.D., of Stony Brook University, and Brian Richmond, Ph.D., of George Washington University, say their finding indicates that the fossil belongs to very early human ancestors, and that upright walking is one of the first human characteristics to appear in our lineage, right after the split between human and chimpanzee lineages. Their findings are published in the March 21 issue of the journal Science.