Lecture 2-2 The Beginnings of Human Culture Lecture Outline To what group of animals do humans belong? When and how did humans evolve? Is the biological concept of race useful for studying physical variation in humans? Anthropology: Four Field Discipline Anthropology includes: – Research on human cultures and languages worldwide and through time. – Paleoanthropologists analyze ancient fossil humans and their ancestors. – Primatologists study the behaviors of our closest animal relatives and other primates. – Others investigate the genetic basis for variations among human populations. Human Cultural Adaptation Cultural adaptations allow people to survive in their environment: – Manufacture and utilize tools. – Organize social units to make searching for food more successful. – Preserve and share traditions and knowledge. Human Cultural Adaptation Computer technology enables us to organize and manipulate information. Space technology may enable us to propagate our species in extraterrestrial environments. Biomedical technology may enable us to control genetic inheritance and the future of our biological evolution. Humans and Other Primates The human species is one kind of primate, a subgroup of mammals that includes lemurs, monkeys, and apes. Humans are most closely related to apes: – chimpanzees, gorillas, orangutans, and gibbons Anatomical Adaptation Preadaptation – Characteristics adaptive to one way of life that also are suitable for a different way of life. Ancestral primates – Preadapted to arboreal life favored by natural selection. Over time – Arboreal life involves changes in various anatomical features. Primate Dentition Diet available to arboreal primates requires unspecialized teeth. Over time, there is a trend toward economy, with fewer smaller teeth doing more work: – Number of incisors decrease. – Number of cusps on molars increases. Dentition Sense Organs Decrease dependency upon sense of smell. Increase dependency upon sight: – Stereoscopic color vision – Corresponding increase in brain size in the visual area More acute sense of touch. Binocular Stereoscopic Vision The Primate Brain An increase in brain size, particularly in the areas supporting conscious thought occurred in the course of primate evolution. In monkeys, apes, and humans the cerebral hemispheres cover the cerebellum, the part of the brain that coordinates muscles and maintains balance. Rather than relying on reflexes controlled by the cerebellum, primates constantly react to a variety of features in the environment. The Primate Brain Messages from hands and feet, eyes and ears, and balance, movement, heat, touch, and pain sensors are simultaneously relayed to the cerebral cortex. The cortex had to develop in order to receive, analyze, and coordinate these impressions and transmit a response back to the motor nerves. The enlarged, responsive, cerebral cortex provides the biological basis for flexible behavior patterns found in all primates, including humans. The Primate Skeleton Opening of the skull for the spinal cord shifts forward toward the skull’s base accommodating upright posture. Snout or muzzle portion of the skull reduced Arms at side rather than the front part of the body Retention of the primate prehensile hand with opposable thumb Primate Skeleton Bison skeleton (left) and Gorilla skeleton (right) Adaptation Through Behavior Arboreal life involved changes in behavior as well as in anatomical features. Learned social behavior plays an important role: – Social behavior rarely observable in fossil record – Examination of contemporary primate behavior may lead to clues to early primate behavior and the emergence of human cultural behavior Chimpanzee Behavior Communities with open subgroups Males generally move Male dominance with mother important in determining rank Maintain strong mother-child bond Grooming is a common pastime Promiscuous sex when female is fertile Settle disputes by aggressive behavior Dependence upon cultural behavior Make and use tools Males hunt in groups and share kill Reconciliation and Its Cultural Modification in Primates There is evidence for reconciliation in more than 25 different primate species. Reconciliation is common mechanism found whenever relationships need to be maintained despite occasional conflict. Chimpanzees are the only animals to use mediators in conflict resolution. Reconciliation is a learned social skill subject to what primatologists now increasingly call “culture”. Human Ancestors Chimpanzees and gorillas – Closest living relatives to humans – Humans, bonobos and chimpanzees 98.5% genetically identical Separation from a common stock – Genetics suggest divergence at least 5.5 million years ago – Fossil evidence shows separation at least 4.4 mya Human Ancestors Ancestors of humans – Most likely apelike animals – Living in Africa – Forced by climactic changes to leave trees Monkeys, Apes, and Humans Molecular evidence indicates the split between the human and African ape lines took place between 8 and 5 million years ago. The First Hominines: Australopithecus Earliest well-known hominine, who lived between 1 and 4.2, if not 5.6 m.y.a. and which includes several species. – Found in eastern Africa and westward into Chad – Fully bipedal – Brain appears apelike – Teeth more like modern humans than apes – Males about twice the size of females – Likely depended upon animal flesh in diet Homo habilis Earliest species of the genus Homo Increased consumption of meat – Living primarily on the savannah – Scavenging from carcasses – Dentition not suited for meat eating, so they probably needed tools to butcher carcasses. – Increased brain complexity and size Homo habilis Culture – Using wits to compete with large animals – Food sharing and preparation – Butchering sites where carcasses are brought Homo habilis Invention of tools about 2.5 million years ago – Oldowan tools •Striking flakes from core – Paleolithic •The Old Stone Age, characterized by chipped stone tools. Homo erectus Species directly ancestral to modern humans Had a body size and proportions similar to modern humans, though with heavier musculature. Average brain size fell within the higher range of H. habilis and the lower range of modern human brain size. Dentition was fully human, though relatively large by modern standards. Homo erectus Culture – Fire and cooking circa 700,000 years ago – Toolkit diversity – New tool making techniques – Selectivity of raw material – Evidence of organized hunting as the means for procuring meat, animal hides, horn and bone. Paleoanthropological Sites Homo sapiens First appear about 300,000 years ago Archaic Homo sapiens – Neanderthal • Europe and Asia • Large brained • Massive face – Other groups found in Java, Zambia, China Modern Homo sapiens • Less massive face • Less bony architecture Anatomically Modern Peoples and the Upper Paleolithic Upper Paleolithic peoples – First people of modern appearance, who lived in the last part of the Old Stone Age. Culture emerges as a more potent force than biology Tools surpass the physical equipment of predators • Bow and arrow Tool Making: Upper Paleolithic A technique used to manufacture blades: The stone was broken to create a striking platform, then vertical blades were flaked off to form sharp-edged tools. Anatomically Modern Peoples and the Upper Paleolithic Art – Decoration – Sculpture – Pendants – Cave painting Ritual – Trance – Burial Race and Human Evolution Anthropologists agree no subspecies exist within currently surviving Homo sapiens. As far as contemporary humanity is concerned, race is not a valid biological category. Anthropologists work to expose the concept of race as scientifically inapplicable to humans. Race as a Cultural Construct Although biological variation exists in the human species, biological races or distinct subspecies do not. Variation such as differences in skin color is the result of genetically adaptive processes to different natural environments. The majority of human variation exists within populations rather than among populations due to – independent inheritance of individual traits – genetic openness of human populations