Hominids

1. Hominids Primates and Human Origins

2. Primate Characteristics • Large brains relative to size – support complex cognitive functions • Acute color vision – Forward facing binocular vision, with depth perception and 3-dimensional acuity • Generalist teeth – Permits herbivorous and omnivorous diets • Communication – Facial and vocal structure allow for broad range of expression • Infant care – Young require prolonged care, requiring reduced litter size

3. Primate Characteristics cont. • Manual dexterity – Opposable thumbs can grip and manipulate objects • Social organization - Complex social groups with complex social behaviors • Characteristic skeletal structures

4. Anthropoids • Members of the suborder Anthropoidea, or anthropoids, include New World monkeys, Old World monkeys, apes, and humans and are distinguished from the prosimians. • Characteristics: • fully binocular vision; • larger brains; • substantial reduction in olfactory organs and nasal area; • improved manual dexterity.

5. Modern Humans • Homo sapiens – bipedal, the only mammal to walk on two legs • Adaptations • Bowl shaped pelvis to support organs • Spine is s-shaped to allow upright posture • Toes much shorter, adapted for bipedalism • Brain much larger than other primates • Extensive areas of brain given to communication

6. Hominids • Include humans and extinct humanlike species • Being bipedal is the distinctive characteristic • All other arthropoids are quadrupedal • When did the first bipedal hominid evolve?

7. Fossil Hominids “Lucy” • A variety of bi-pedal hominids have lived on the earth over the past 10 million years • The debate continues as to the relationships between different hominids Discovered in 1974, is 3.2 million years old.

9. Humans • Members of the Genus “Homo” are known as humans, they include Homo sapiens and several extinct species • The earliest “humans” include Homo habilisand Homo erectus, both had brain capacities significantly less than Homo sapiens • Other humans include Homo neanderthalensis, who lived from 230,000 to 30,000 years ago. They had brain capacity similar to modern day Homo sapiens and the reason for their extinction is still a puzzle.

10. Modern Humans • Oldest fossils found so far are perhaps 195,000 years old. • Found in Africa (Ethiopia). • Two hypotheses • Multiregional Hypothesis - local populations of Homo erectus gave rise to local populations of Homo sapiens all over the world • Out of Africa Hypothesis – Homo sapiens evolved from Homo erectus uniquely in Africa before migrating out of Africa and populating the globe

11. Human migration