Dating human past culturally

In his work on biology, he avoided the effort to treat biological entities by the use of rigid formal logic, and, though he made some inevitable errors in fact, his pragmatic approach has served as a model for biological observation ever since.From long before the time of the ancient Greeks, human beings were generally recognized as members of the animal world.Much later, in the middle of the 19th century, Charles Darwin, in his brilliant book 'On the Origin of Species by Means of Natural Selection' (1859), forced the world to face the fact that all the living creatures of the world had almost certainly descended from a common ancestor.He further developed that view in his work 'The Descent of Man' (1871), in which he specifically stated that humankind ultimately shared a common origin with the rest of animate nature.

The period of human evolution has coincided with environmental change, including cooling, drying, and wider climate fluctuations over time.This measure can be used as an indicator of changing temperature and glacial ice over time.There are two main trends: an overall decrease in temperature and a larger degree of climate fluctuation over time.The δO trend has been toward a cooler, glaciated world.However, the amplitude of oscillation also increased beginning around 6 Ma, and became even larger over the past 2.5 Ma.