period of time before people started writing

human beings and the humanlike creatures that preceded them 

study of prehistoric life

people who study hominids-their physical features, development, and behavior; they compare hominid bones and fossil sizes

used to determine the age of a once-living organism; once-living things contain small amounts of radioactive carbon; because carbon decays at a known rate, archaeolgists can measure how much radioactive carbon has decayed and figure out when the plant or animal has died

a site in Ethiopia where the oldest hominid teeth were ever found by Gen Suwa

a 3.2 million year old hominid skeleton found at Hadar; most nearly complete skeleton of any erect-walking prehuman found up to that time

First prehuman hominids that date back 4.4 million years; also called "southern ape."  They stood 3.5 to 5.0 feet tall and walked on two legs; they had large faces that jutted out; small brains, flat noses, and large teeth; the back teeth were suitable for grinding food; they were nomads.

Earliest of the 3 hominid groups; name means "person with ability"; lived about 1.5 million years ago.  Oldest hominids known to manufacture tools.  Larger brains indicate physical and mental advances.  Migrated and used gestures and grunts to communicate.

Second oldest group; name means "person who walks upright."  First just food gatherers but learned to hunt using spears and clubs.  Learned how to make fire which helped for warmth, food, and scaring off predators.  Lived in caves.

Name means "person who thinks"; all people living today belong to this species. 

Four long periods of cold climate; temps fell below freezing, glaciers spread out from the Poles, scarring the landforms over which they crept.  Only middle latitudes remained warm enough to support human and animal life.  Humans responded to Ice Ages by migrating to warmer places, using clothing, and making fire.

the ability to walk upright on two feet