Human Evolution

Mammal Characteristics Produce milk for young Hair Differentiated teeth Embryos develop inside and gain nutrients from the mother (placentals)

Primates Order of animals in class Mammalia 3 main groups: lemurs, tarsiers, and anthropoids (monkeys, apes and humans)

Primate Characteristics Open shoulder structure Legs and feet designed to bear majority of the individual’s weight Well developed fingers Fingernails and Toenails (not claws) Opposable thumbs

Continued Hip and shoulder joints allow a wide range of motion Eyes directed forwards – Binocular vision = both eyes view the same objects simultaneously with slightly different angles Large and complex brains Omnivorous One offspring at a time

What makes humans unique from other primates? Larger and more complex brain Capable of language Completely bipedal Hands are better adapted for precise movement Manufacture and use complex tools

Where did we come from? Homo sapiens = only species of human that still exists – 20 extinct species that are more closely related to humans than chimps (hominims) Fossil records help us study our ancestors – Focus on pelvis, backbone, skull, jaws and teeth Molecular comparisons determine relatedness – Chimpanzees = closest living relative

Relatives Hominids – Bipedal, human-like animals that belong to the same family as modern humans – Appeared approx. 4 million years ago – 2 genera – Homo and Australopithecus (Lucy) – 2.5 million years ago hominids began to use tools – 1.5 million years ago hominids became more widely distributed throughout the world (Homo erectus) – 160,000 years ago = early modern humans eventually lead to Homo sapiens – Current debate over modern human lineage Not a linear progression but a branching phylogeny