HW Human Evolution 8/1/15
Human Evolution has spanned approximately 85 million years, but Homo sapiens have only existed for the last 400,000 years. During this time we have changed our behaviors in many ways, due to changes in natural selection and physiology. This is most evident when comparing the current human skeleton to that of Lucy and Ardi's skeleton, two females who lived 3.2 and 4.4 million years ago respectively. The examples I am going to look into in this essay is the conscience, the use of modern courtship and the existence of the tail bone. There has always been controversy surrounding evolution, with 40% of Americans believing in young earth creationism and 38% believing that evolution has been overseen by God. This leaves a very small percentage of Americans which are supported by all scientific evidence in reasonable experimental conditions. In the courts, they frequently use the same line, that evolution is only a theory. That is true, and it is promising, because it could mean that they have read into the papers and challenged its conclusions with its own scientifically relevant evidence. More often than not this is not the case. Some disagree with the evidence of evolution because it has never been directly observed. In the words if the great George Carlin 'some people won't believe in evolution before they see a monkey give birth to a human'

Ardi is a fossil of Ardipithecus ramidus, an early form of hominid. She was discovered in Ethiopia and is believed to be 4.4 million years old. The skeleton displayed a mixture of features found in humans. This evidence included the structure of the feet, which showed that she had a large big toe to climb trees. She also had short legs and long arms, a brain the size of a chimp and a leg structure which suggested she walked upright but used her hands to help, like an ape.

Lucy is a fossil of the Australopithecus afarensis. She was also discovered in Ethiopia and is believed to be 3.2 million years old and shows development from Ardi. Lucy has arched feet which aids walking, rather than climbing. The size of her arms was more balanced, her brain was bigger and she walked upright, more effectively than Ardi.

The final example of fossil evidence is the group of hominid fossils found in Kenya by Richard Leakey, where he was born. He found the remains of a Turkana boy – a fossil skeleton of homo erectus. He had some ape-like features but is more human than Lucy. He has short arms, a brain size similar to that of a human and the structure of his legs and feet suggests he was better adapted to walking upright than Lucy.

This evidence was approved using carbon dating, where objects can be given approximate dates by measuring the decay of carbon atoms. It is a type of radiometric dating. The method uses the radioactive isotope carbon-14, most organic matter contains this firm if carbon. Carbon has different isotopes, which are usually not radioactive; 14C is the radioactive one, its half-life, or time it takes to radioactively decay to one half its original amount, is about 5,730 years.

These examples of fossil evidence are frequently cited as evidence to display the progression of human anatomy. This is shadowed by the progression of tools, but they cannot be carbon dated. They only say how old the rock is. As humans became more advanced, so did our tools. We moved to sharpen rocks and use fire. We also used handles and tied things with ropes. The ecology of human behavior is a discipline of psychology that holds that humans are basically behave as rational actors who tend to maximize their biological efficacy adapting to medium concrete living. Individuals act as if there were a genotype only human who gives us a mind able to develop different types of culture in terms of the different environments. Examples of these behaviours include being able to swim as a baby but then being needed to be retaught.

As modern humans were leaving Africa around 60,000 years