Physical anthropology is also called biological anthropology. You need to understand the basics of biology before you apply it to humans. We are going to use these ideas as the basis for explaining phenomena in later sections, such as: Why primates scream at each other? How are those two fossils related? Why do people look different from each other? What are people going to look like in a million years? Now is a great time to review your notes from your High School biology class.
Biology is a broad field that ranges in scale from the microscopic to the geographical. Evolutionary theory is crucial to biology. Charles Darwin's theory of natural selection came from a historical context where many other scientists were contributing to evolutionary theory. Natural selection means that individuals compete for resources and those with the variations that make them more fit to survive in a certain environment tend to survive and reproduce more. Sexual selection is the part of natural selection that focuses on competition for reproduction. Darwin understood the importance of variation.
Gregor Mendel used math to explain how variation is inherited. Population genetics used math to show how inheritance works in large populations. The modern synthesis combined Mendelian genetics and population genetics, to codify evolutionary theory into four forces: mutation, natural selection, migration, and genetic drift. Inheritance, mutation, and other sources of variation can now be understood through cellular biology and genetics. Humans are made up of cells. Cells have DNA. DNA is the code that directs protein synthesis. Proteins direct the functions of life.
Sickle cell anemia is an example of how the holistic approach of anthropology can use many subfields, mostly from biology, to understand the origins and consequences of an important human disease.