Chapter 43Mammals

Section 4

Primates & Human Origins

Primate Characteristics• Prehensile appendages- hands,

feet, and tails can grasp• Large brain- allows for complex

skills- interacting socially, parental care, using hands, interpreting visual information

• Acute color vision- forward facing eyes for depth perception

Primate Characteristics• Generalist teeth- herbivorous and

omnivorous diet

• Communication- facial and vocal structure

• Infant care- infants require care- usually one pair of mammary glands on the chest

Primate Characteristics• Manual dexterity- opposable thumbs,

flattened nails protect finger pads• Social organization- live in social

groups• Characteristic skeletal structure- sit

upright, cling to trees

Anthropoids• Anthropoid primates- gibbon- New

World monkeys, Old World monkeys, apes, and humans

• Adaptations: rotating shoulder, elbow joints, opposable thumb- can touch other fingers

• Grasping feet

New World monkeys- orangeOld World monkeys- red

Anthropoids• Humans, apes, and Old World

monkeys- similar dental structures

• Anthropoids have a larger brain structure

• Great apes- orangutans, gorillas, chimpanzees, bonobos, and humans

Anthropoids• DNA sequence- humans are more

closely related to chimpanzee than chimpanzee related to gorilla

• DNA & fossil evidence suggest that humans and chimps share a common ancestor

• Humans did NOT descend from chimps- evolved from common ancestor

Modern Humans• Bipedalism- tendency to walk upright

on two legs• Bowl-shaped human pelvis • S-shaped spine• Toes are aligned • Large brain, smaller jaw• Apes communicate & humans reason

with communication

Hominids• Hominids- humans and extinct

humanlike anthropoid species

• Bipedalism

• All other primates are quadrupedal

Fossil Hominids• Paleontologists & anthropologists

(scientists who study humans) found fossil evidence of humanlike species

• 1974- Afar Valley region of Africa by Donald Johanson and colleagues founded a bipedal fossil of early human ancestor

Australopithecines• Australopithecus afarensis- “Lucy”

• Additional fossils of Lucy have been discovered in the same area

• Australopithecines- subfamily

Many Hominid Species• 1995- Mary Leakey- found

Australopithecus afarensis

• Similar to Lucy and chimpanzees

Humans• Humans- extinct and living

members of this genus (Homo)

Homo habilis & Homo erectus

• 1960s- hominid skull- larger brain capacity than Lucy- Homo habilis

• Homo erectus- (“upright human”)- brain capacity of 2/3 modern human size- scientists think these were the first humans to travel out of Africa

Homo sapiens & Homo neanderthalensis

• Neanderthals- Europe & Asia

• Lived in caves & made tools out of stone

• May have interacted with Homo sapiens

• H. Sapiens- first humans- France (first fossil)

Modern Humans• Mitochondrial DNA suggests

humans originated from Africa

• Interbreeding of humans helped populate the world full of the human race

REVIEW!!!• Identify which characteristics

humans share with primates and which are unique to humans.

• What kind of evidence shows that chimpanzees are the closest living relatives of humans?