Hominid Evolution What is a Primate A primate

Hominid Evolution

What is a Primate? � A primate is a mammal that has: �relatively long fingers and toes with nails instead of claws �arms that can rotate around shoulder joints �a strong clavicle �binocular vision �a well-developed cerebrum.

Hominoid vs. Hominine �Hominoid: � Group of animals that belong to the same Family. � Lack a prehensile tail � Includes gibbons, orangutans, gorillas, chimpanzees and humans.

Hominoid vs. Hominine �Hominine: �The hominoids in the lineage that lead to humans. �Evolved the ability to walk upright �Had grasping thumbs and large brains

Check Up #1 Which of the following is not considered a hominoid? a) Orangutan b) Chimpanzee c) Rhesus monkey d) Human

Living Hominids

Hominine Evolution � The skull, neck, spinal column, hip bones, and leg bones of early hominine species changed shape in ways that enabled later species to walk upright.

Bipedalism Placement of the Foramen Magnum reveals the posture of the organism Grasping toes – demonstrates that the organism is adapted to living in trees

Hominine Evolution � This figure shows some ways in which the skeletons of modern humans differ from those of hominoids such as gorillas.

Hominine Evolution �Hominines evolved much larger brains. �Most of the difference in brain size results from an expanded cerebrum, which is, as you recall, the “thinking” part of the brain.

Teeth • Identify the differences you see in the teeth of these three species. • Interpret: what are two explanations for the differences?

Hominid Characteristics

Other Characteristics

Check Up #2 �What changes in environment supported Hominoid characteristics over earlier primates? �A)

Relatives vs. Ancestors � The hominine fossil record includes seven genera— Sahelanthropus, Orrorin, Ardipithecus, Australopithecus, Paranthropus, Kenyanthropus, and Homo—and at least 20 species. � All these species are relatives of modern humans, but not all of them are human ancestors.

Relatives vs. Ancestors

�Which probably evolved first, large brain or bipedalism? Why?