Jerry Monaco's List: evolution

• evidence that the evolutionary split between hominins (the group that includes modern humans and their ancestors) and great apes (gorillas and chimpanzees) involved a major change in diet.
• uring the Pliocene geological epoch (5.3 to 2.6 mya) extensive tropical woodland areas in Africa began to shrink in response to gradual drying and cooling of the climate, which eventually led to the ice ages of the Pleistocene. Populations of the last common ancestor were faced with the option of either trying to survive in the shrinking forests or to venture out onto the expanding grasslands. Those that did the former eventually became the modern great apes. Those that followed the latter course evolved into hominins. A number of lines of evidence have helped to elucidate this transition.
• Evidence of bipedalism can be clearly seen in the major modifications to the skeletons of early hominins, in particular the feet, lower limbs, pelvis, and spine.

• Based on their data, the researchers propose that Australopithecus afarensis was a “generalist omnivore,” consuming a wide variety of plants, insects, and even small game, perhaps by scavenging.

  Data derived from specimens of Australopithecus africanus and Paranthropus, South African hominins that date to around 2.5 mya, indicate a continuing omnivorous diet, including both C3 and C4 plants for the former and a focused C4 plant diet for the latter, suggesting a concentration on grasses. Paranthropus, the specialized grazer, eventually became extinct. Australopithecus africanus, on the other hand, may be closely related to the earliest members of the genus Homo,
• dietary flexibility may have been an important component of human adaptation.
• The next big shift in hominin diet occurred with the appearance of the earliest members of the genus Homo, about 2.5 million years ago (overlapping in time with the later australopithecines), when the first evidence of stone tool use as well as of meat consumption is found.
• the apparent lag between the adoption of bipedalism and the dietary shift.

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• Nagel opposes two main components of the “materialist” view inspired by Darwin’s theory of evolution by natural selection. The first is what we will call theoretical reductionism, the view that there is an order of priority among the sciences, with all theories ultimately derivable from physics and all phenomena ultimately explicable in physical terms. We believe, along with most philosophers, that Nagel is right to reject theoretical reductionism, because the sciences have not progressed in a way consistent with it. We have not witnessed the reduction of psychology to biology, biology to chemistry, and chemistry to physics, but rather the proliferation of fields like neuroscience and evolutionary biology that explain psychological and biological phenomena in terms unrecognizable by physics. As the philosopher of biology Philip Kitcher pointed out some thirty years ago, even classical genetics has not been fully reduced to molecular genetics, and that reduction would have been wholly within one field. We simply do not see any serious attempts to reduce all the “higher” sciences to the laws of physics.
• The second component of the thesis Nagel opposes is what we will call naturalism, the view that features of our world—including “consciousness, intentionality, meaning, purpose, thought, and value”—can ultimately be accounted for in terms of the natural processes described by the various sciences (whether or not they are ever “reduced” to physics). Nagel’s arguments here are aimed at a more substantial target, although he gives us few specifics about the kind of naturalism he opposes. He does characterize it as the attempt to explain everything “at the most basic level by the physical sciences, extended to include biology,” and the one named proponent of this view is the philosopher Daniel Dennett. Although Dennett would not characterize his project as trying to explain everything at the “most basic level,” he does aim to show that phenomena such as consciousness, purpose and thought find a natural home in a picture of human beings inspired by Darwin. In the absence of any clearer statement of the argument, we will assume that this is the so-called “neo-Darwinian” picture that Nagel opposes.

• Several things, but consider one: the contention that evolution may tend towards consciousness. Nagel is explicit that he himself is not countenancing a designer. Rather, he wonders whether science needs to entertain the possibility that a teleological trend is immanent in nature.

  There it is. The t-word – a major taboo among evolutionary biologists. Goal-directed explanations automatically question your loyalty to Darwin. As Friedrich Engels celebrated, when reading On The Origin of Species in 1859: "There was one aspect of teleology that had yet to be demolished, and that has now been done." But has it? This is the moot point.

• Plenty of mammals, like chipmunks, live in trees but don’t have nimble hands or closely spaced, forward-facing eyes that allow for good depth perception. Instead, Cartmill suggested these features evolved because early primates were insect predators. He noted that many modern predators, such as cats and owls, have forward-facing eyes because they rely on good vision to grab prey. In the case of early primates, Cartmill said, they hunted tree-dwelling insects.
• Primates evolved in step with the spread of flowering plants. Rather than relying on good vision and dexterity to nab bugs, early primates used these traits to carefully walk out to the ends of delicate tree branches to gather fruits and flowers, as well as the insects that pollinated flowering plants.