Physical Anthropology: primate evolution

1. Physical Anthropology: primate evolution

2. By the end you should know... • Taxonomy classification terms • When and where the first primates evolved • Characteristics that distinguish different primate groups • Various aspects of primate behavior

3. Taxonomy • We organize all life into groups, called taxons, thanks to Carle Linneaus.

4. ORDER: Primate • FAMILY • Hominoidea (this is a actually a super family of chimps, gorillas, orangutans, great apes, humans and our ancestors) • Broken into Families: Hominoidae (humans and apes) and Pongidae • Lepilemuridae (several lemur species) • Atelidae (howler and spider monkeys) • GENUS • There are several! Examples: • Papio(the baboons) • Pongo(some chimps) • Pan (some chimps) • Homo (humans and our ancestors) • SPECIES • There are about 200 species of primates today!

5. Today’s Primate Order • Today’s primates, although they vary a great deal, share some similiarities, such as: • Wide range of body size (100g to 200kg), but most average around 10 pounds • Large eyes with 3D depth perception • Focus on vision rather than smell (small noses) • Large brain (larger brain to body mass ration than any other animal) • Heterodont teeth (different teeth) for a varied diet • Nails rather than claws

6. Primate Origins • Earliest fossils have been dated 65 million years ago in Africa. What else happened 65 million years ago? • Bone fossils are bones that have been replaced with minerals, creating an exact replica. • First primate were very small (150g to 3kg), and had teeth that showed that they ate insects • They were arboreal (lived in trees) and looked kind of like a squirrel!

7. Teeth • Anthropologists use dental formulas to compare humans to other primates. • Humans have: • 2 incisors • 1 canine • 2 premolars • 3 molars • This reads 2-1-2-3 • Monkeys are 2-1-3-3

8. Different teeth • Incisors: Thin, blade like teeth at the front of the mouth for snipping and clipping • Canines: The pointed, conical teeth used for puncturing and light crushing • Premolars: Somewhat pointed, but somewhat jagged for light crushing • Molars: Heavy, flat teeth in the back of the mouth for heavy crushing

9. What Do Primates Eat? • Primates exploit a variety of food sources. Most primates eat: • Fruit for carbohydrates and lipids • Leaves or insects for proteins, vitamins, and minerals • Some prosimians can make their own Vitamin C! • Many primates have anatomical specializations (such as teeth and specialized digestive tracts) that enable them to exploit particular foods, such as fruit, leaves, gum or insects • Tarsiers are the only primates that are obligate carnivores • The common chimpanzee will predate on other primate species, such as the western red colobus monkey. This sometimes involves tool use. Common chimpanzees sharpen sticks to use as weapons when hunting mammals.

10. How do Primates Move? • Brachiation: arm swinging for arboreal locomotion • Usually small gibbons and siamangs • Bipedalism and Quadrupedalism: walking on 2 legs and 4 legs, respectively • Knuckle-walking: a form of quadrupedal walking, in which the forelimbs hold the fingers in a flexed posture that allows body weight to press down on the ground through the knuckles • Climbing and leaping are also used

11. Primate Social Behaviors • Primates have several different categories of social systems. They are affected by 3 main things: • Distribution of resources • Group size • Predation • Within a social group there is a balance between cooperation and competition. • Cooperative behaviors include social grooming (removing parasites and cleaning wounds), food sharing, and collective defense against predators and territory. • Aggressive behaviors often signal competition for food, sleeping sites or mates. Aggression is also used in establishing dominance

12. Social Groups • Female transfer systems – females move away from the group in which they were born.. The groups formed are generally quite small. This organization can be seen in chimpanzees • Male transfer systems – while the females remain in their natal groups, the males will emigrate as adolescents. Group sizes are usually larger. This system is common among the lemurs and some species of monkeys. • Monogamous species – a male–female bond, sometimes accompanied by a juvenile offspring. There is shared responsibility of parental care and territorial defense. The offspring leaves the parents' territory during adolescence. • Solitary species – often males who defend territories that include the home ranges of several females. This type of organization is found in many lemurs and orangutans.

13. How Smart Are They? • Primates have advanced cognitive abilities: some make tools and use them to acquire food and for social displays • Some have sophisticated hunting strategies requiring cooperation, influence and rank • They are status conscious, manipulative and capable of deception • They can recognise their kin • They can learn to use symbols and understand aspects of human language including some relational syntax and concepts of number and numerical sequence • Comparative studies show a trend towards higher intelligence going from prosimians to New World monkeys to Old World monkeys (larger), and significantly higher average cognitive abilities in the great apes.

14. Apes • Most human-like • DNA is extremely close to ours • Fossils date back to 30mya • 6mya, the Family Homindae appeared • Dental formula 2-1-2-3 • Lack of tail • Terrestrial life style, not just arboreal • Relatively long arms • Simple molars for crushing, rather than shears • Relatively large body mass • Eventually some evolved into the genus Homo, which are the ONLY bipedal primates

15. Bipedal Primates (humans) • Relatively long strong legs • An S-shaped spinal column that can absorb stress • A wide pelvis that keeps the thighs apart to help balance • A parallel big toe lined up with the rest of the toes (rather than a grasping toe) • Thighs that angle inward toward the knees to help balance • Lateral and transverse arches built into the foot so that we have a “tri-pod” and are not flat footed

16. Endangered Primates • Several species of chimps, apes, gibbons, orangutans are endangered due to: • Habitat destruction from logging, mostly in Southeast Asia and Breo (home of the orangutan) • Habitiat destruction from agriculture in the African Congo (where the gorillas live) • Poaching  (mostly for meat)

17. Endangered Prosimians • Prosimians are a suborder of the Order Primates (include lemurs, aye-aye, galagos) • All 50 species are endangered due to deforestation • Most live on Madagascar, an island off of Africa • www.wildmadagascar.org

18. DEBATE • After analyzing humans, and how primates evolved, how they eat, how they act, how they are anatomically similar, how they communicate and socialize, how they live and reproduce, and how their DNA is so similar to humans, should the Genus Pan be included in the Genus Homo? • Why can’t the Pan be with the Homo, and just have different species? Why do we have to make distinct genuses? • Research the issue, and be prepared to debate next class!