PHYSICAL ANTHROPOLOGY:

PRIMATE EVOLUTION

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

Taxonomy We organize

all life into groups, called taxons, thanks to Carle Linneaus.

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)

GENUSThere are several! Examples:

○ Papio (the baboons)○ Pongo (some chimps)○ Pan (some chimps)○ Homo (humans and our ancestors)

SPECIESThere are about 200 species of primates today!

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

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!

Teeth Anthropologists use dental formulas to

compare humans to other primates. Humans have:

2 incisors1 canine2 premolars3 molars

This reads 2-1-2-3 Monkeys are 2-1-3-3

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

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.

How do Primates Move? Brachiation: arm swinging for arboreal

locomotionUsually 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

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

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.

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.

Apes Most human-like DNA is extremely close to ours Fossils date back to 30mya 6mya, the Family Homindae appeared

Dental formula 2-1-2-3Lack of tailTerrestrial life style, not just arborealRelatively long armsSimple molars for crushing, rather than shearsRelatively large body mass

Eventually some evolved into the genus Homo, which are the ONLY bipedal primates

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

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)

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

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!