Humans (Homo sapiens) are the only extant members of the subtribe Hominina. Together with chimpanzees, gorillas, and orangutans, they are part of the family Hominidae (the great apes, or hominids). A terrestrial animal, humans are characterized by their erect posture and bipedal locomotion; high manual dexterity and heavy tool use compared to other animals; open-ended and complex language use compared to other animal communications; larger, more complex brains than other animals; and highly advanced and organized societies. Early hominins—particularly the australopithecines, whose brains and anatomy are in many ways more similar to ancestral non-human apes—are less often referred to as "human" than hominins of the genus Homo. Several of these hominins used fire, occupied much of Eurasia, and the lineage that gave rise to Homo sapiens is thought to have diverged in Africa around 500,000 years ago, with the earliest fossil evidence of evidence of early Homo sapiens appearing (also in Africa) around 300,000 years ago. The oldest early H. sapiens fossils were found in Jebel Irhoud, Morocco dating to about 315,000 years ago. Omo-Kibish I (Omo I) from southern Ethiopia is the oldest anatomically modern Homo sapiens skeleton currently known (196 ± 5 ka). Humans began to exhibit evidence of behavioral modernity at least by about 100-70,000 years ago and (according to recent evidence) as far back as around 300,000 years ago, in the Middle Stone Age, (with some features of behavioral modernity possibly beginning earlier, and possibly in parallel with evolutionary brain globularization in H. sapiens). In several waves of migration, H. sapiens ventured out of Africa and populated most of the world. The spread of the large and increasing population of humans has profoundly affected much of the biosphere and millions of species worldwide. Advantages that explain this evolutionary success include a larger brain with a well-developed neocortex, prefrontal cortex and temporal lobes, which enable advanced abstract reasoning, language, problem solving, sociality, and culture through social learning. Humans use tools more frequently and effectively than any other animal: they are the only extant species to build fires, cook food, clothe themselves, and create and use numerous other technologies and arts. Humans uniquely use such systems of symbolic communication as language and art to express themselves and exchange ideas, and also organize themselves into purposeful groups. Humans create complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established an extremely wide variety of values, social norms, and rituals, which together undergird human society. Curiosity and the human desire to understand and influence the environment and to explain and manipulate phenomena (or events) have motivated humanity's development of science, philosophy, mythology, religion, and numerous other fields of knowledge. Though most of human existence has been sustained by hunting and gathering in band societies, many human societies transitioned to sedentary agriculture approximately 10,000 years ago, domesticating plants and animals, thus enabling the growth of civilization. These human societies subsequently expanded, establishing various forms of government, religion, and culture around the world, and unifying people within regions to form states and empires. The rapid advancement of scientific and medical understanding in the 19th and 20th centuries permitted the development of fuel-driven technologies and increased lifespans, causing the human population to rise exponentially. The global human population was estimated to be near 7.8 billion in 2019.