Biological anthropology strives to understand how humans interact and behave in the present, how humans evolved biologically, and how humanity’s ancient ancestors lived in diverse climates and environments. The anthropological approach to exploring these questions is grounded in evolutionary theory. Charles Darwin was one of the first to propose a mechanism by which evolution occurred, which he called natural selection. Natural selection is based on the premise that those with more favorable characteristics survive and reproduce at greater rates than those without them. Natural selection depends on the evolutionary processes of mutation, speciation, gene flow, and genetic drift.
Darwin’s theory did not address how these favorable characteristics could be inherited. Gregor Mendel’s experiments on peas addressed this very question. Mendel’s work resulted in two very important observations. He observed that the two alleles for each trait separate during the formation of the sex cells and that the probability of having one trait does not affect the probability that an individual will have another trait.
Carolus Linnaeus is best known for creating the classification system that taxonomists use today, which is based on physical similarities and differences. Phylogenetics is a hypothesis about how species are related to one another and to a common ancestor. Today, biological anthropologists apply taxonomies and phylogenies to the current nonhuman primate and hominin fossil record. It is in the Miocene that the first fossil apes, such as Proconsul, are seen. The first evidence of hominin-like fossils appears by the end of the Miocene. A large number of morphological changes observed in early hominins suggest considerable environmental and climatic change. During the Pliocene epoch, extending from 5 to 1.8 MYA, the evolution of hominins that were clearly bipedal is evident in the fossil record, as is evidence of cultures that used stone tools. The path is now ready for the next group in humanity’s evolutionary history to enter the scene.