2/9/11

Today, we took a quiz.
Notes:

Human Ancestry

• Early primates:
  
  evolved from insect-eating mammals during Cretaceous period (evidence from fossils)


• were small


• lived in trees (arboreal)


• limber shoulder joints


• could grab with their hands (dexterous)


• nails started replacing claws


• had depth perception (eyes close together in front of face)


• eye-hand coordination


• parents cared for their offspring

The 2 Major Primate Groups:

Prosimians

• oldest


• EX- lemurs, lorises, pottos, tarsiers

Anthropoids

• 
  EX-monkeys, apes, humans


• New World monkeys


• in the Americas


• arboreal


• prehensile tails-could swing by tails and grab things with them unlike dogs or cats, it functioned as an extra appendage


• Old World monkeys


• mostly ground dwellers


• EX- baboons-


• -Prehensile tail, New World

Human Ancestors

• closest anthropoid relatives=apes
• gibbons, orangutans, gorillas, chimps
• apes today live in tropical regions of Old World
• Humans
• young twig on vertebrate branch
• chimps and humans diverged from common ancestor 5-7 million yrs. ago

• Our ancestors are not modern apes and chimps; we diverged on a different branch than they did, but we both evolved from a common ancestor
• they are more like our cousins than anything else

• Human evolution is not a series of steps leading directly from an anthropoid ancestor to Homo sapiens; other groups have traveled to dead ends and died off
• Many different human species coexisted
• We are a subspecies of Homo sapiens

• Human characteristics did not evolve at the same time
• They evolved at different rates
• Bipedalism-walking on two feet, led the way
• We had some ancestors who walked on two feet and upright, but they still had ape-sized brains

Kinds of Hominids

Australopithecus-walked African savanna, came before Homo genus:

• A. afarensis
• early species
• bipedal
• a skull was found that was about 3.9 million yrs. old. It had a vertical backbone which provided evidence that upright posture is at least that old
• Lucy-very complete skeleton of A. afarensis, female, 3ft tall, 3.2 million yrs. old
• footprints also found, bipedal footprints in Africa, 3.7 million yrs. old
• bipedalism is a very old trait
• Australopithecus went extinct about 1.4 million yrs. ago

Homework!!

Lab 32-due Monday

Up pgs. 69-70, read and questions

Next scribe:

Aliza!! :)