Anthropology is the study of humans, human behavior, and societies in both past and present. It seeks to understand the diversity of humans and how and why they differ physically and culturally. There are four main fields of anthropology: biological anthropology, which studies human populations and evolution using an evolutionary framework; archaeology, which seeks to reconstruct past human cultures; cultural anthropology/ethnography, which aims to understand cultural variation across societies; and linguistic anthropology, which examines human language and communication and how it relates to culture.