Human Evolution Exam 2 Primates

class of primates

mammals

primates have

greater than 200 species

monotreme

lays eggs

marsupial

pouched animals

placental

"true mammals"

primates

wet nose

Strepsirrhines : 23 families

dry nose

Halplorhines : 44 families

primate habitats

tropical or semitropical areas

close to water

arboreal

in trees

primate taxonomy

order : primates

Halplorhini (sub order) includes

Tarsiiformes (tarsiers), Anthropoidea (monkeys, apes, humans)

Catarhini divided into two superfamilies

Cercopithecoidea (old world monkey)

Hominoidea (apes and humans)

Strepsirrhini (sub order) includes

Lemuriformes (lemurs) and Lorisformes (lorises)

Cercopithecoidea divided into two subfamilies

Cerpithecines and Colobines

Cerpithecines

from Africa

Eat fruit (frugivore)

have cheek pouches

Colobines

from Asia

eat leaves (herbivore)

Hominoidea divided into two families

Hylobatidea, Hominidae

hominidae divided into three subfamilies

ponginae (pongo / organutans)

gorillinae (gorillas)

homininae (chimps bonobos humans)

homininae divded into two tribes

panini (pan - chimps)

hominini (homo - humans)

Hylodatidae

quadruped

small body

furred

(gibbons)

Pongidae

quadruped

large body

furred

(organutan)

Homininae

biped

large body

fairly naked

(chimps humans)

homology

similarity due to common ancestry

homoplasy

no common ancestor

process by which similarities can develop in different organisms

ancestral (primitive)

characters that are inherited by a group of organisms from a remote ancestor

derived (modified)

characters that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages

(primate characteristics) hands and feet

grasping ability

5 digits

opposable thumb and big toe

tactile pads and nails

(primate characteristics) brain and senses

color vision

stereoscopic/binocular vision

reduced sense of smelling ability (olfactory ability)

larger/more complex brains

(primate characteristics) diet and teeth

heterodont (4 different typed of teeth)

dietary variation

(primate characteristics) limbs and locomotion

tendency toward erect posture

flexible, generalized limb structure

locomotor variety

(primate characteristics) maturation, learning, and behavior

longer gestation and life span, fewer offspring, delayed maturation

learned behavior

social groups

typically dinural

Nocturnal

night active

lemurs/lorises

tarsier

aotus

dinural

day active

monkeys/lemurs

apes

crepuscular

dawn/dusk active

bats

eulemur macaco

polygynous (primate social groups)

one male

multifemale

polyandry (primate social groups)

one female

multimale

polygamous (primate social groups)

multimale

multifemale

monogamy

one male

one female

solitary (primate social groups)

all male

arboreal hypothesis

Primates diversified in arboreal habitats

Visual Predation Hypothesis

primate emphasis on vision due to preying on cryptic insects in trees

primates need stereoscopic vision in complex three dimensional environment

angiospem coevolution hypothesis

primates evolved to forage on fruits in the terminal branches of trees

functional morphology

Studying the relationship between what something looks like and how it works

forelimb longer

suspension/brachiation

hindlimb longer

leaping/bipedal

equal length limbs

quadruped

terrestrial quadrupedism

walking on all 4 limbs on the ground

all 4 limbs equal

restricted joints

narrow to deep body

arboreal quadrupedism

walking on all for limbs in trees

all 4 limbs equal

more rotation ability in wrists and ankles

more loose/compliant posture

vertical clinging and leaping (VCL)

leaping from vertical support to next vertical support; seen in Strepsirrhines and Tarsiers

longer hindlimbs

enlarged hands and feet

suspension (hominoids)

under branch hanging; support body weight and moving primarily under branches

longer forelimbs

extreme rotational ability

wide and shallow

omnivores

fruits, leaves, insects

can infer diet by looking at:

body size

dental form

- esp. molars

dentition

teeth can be grouped based on their shape

tooth shape is related to its function

incisors

anterior, wedge-shaped

propagating cracks

canines

behind incisors, pointed

puncturing

premolars

behind canines, bicuspid

crush and grind food

double-cusped teeth behind canines used for preliminary crushing and grinding

molars

posterior, multiple cusps

crush and grind food

Insectivore/Faunivore Dentition

Tarsier

incisors- small pointy

molars- sharp pointy cusps

Frugivores

fruit eating

low rounded cusps

apes have Y-5 cusp pattern

Frugivory (teeth)

broad incisors

- cutting fruit

low rounded molar cusps

- grinding fruit to pulp

Folivores

leaf eating

molars

- shearing crests; cutting leaves

OWM bilophodont dentition

Folivory (dentition)

incisors - narrow

molars - shearing crests

Strepsirrhines

Lemurs and Lorises

rely on olfaction

wet rhinarium (wet nose)

laterally placed eyes

shorter gestation and maturation periods

eye shine (help see at night) (tapetum lucidem)

tooth comb

tooth comb in

strepsirrhines

lower incisors and canines

procumbant

Haplorhines

monkeys, apes, humans

larger brain and body size

reduced olfaction

post-orbital closure

longer gestation and maturation periods

fused mandible and frontal

monkeys : old and new world

70% of all primates

two groups separated by geography and several million years of evolution

New World Monkeys location

central and south america

old world monkeys location

africa europe asia

Platyrrhines

marmosets, capuchins, atelines

only nocturnal monkey (Aotus)

prehensile tail

2.1.3.3.

arboreal quadrupeds; some leaping

Old World Monkeys (Catarrhini)

Cercopithecoidea

baboons, colobines

2.1.2.3.

all dinural

bilophodont molars

sexual dimorphism

Cercopithecoid

large monkeys

dinural

mainly quadrupedism; some leaping

diet : leaves

Hominoids (apes and humans)

larger than monkeys

no tail

increased brain size

low rounded smaller cusps (Y-5)

2.1.2.3

Gibbon (asian lesser ape)

hylobates

5-12 kilos

brachiator - under branch hanging/swinging

monogamous

orang-utan (asian great ape)

pongo pygmaeus

female: 36 kilo

male: 76 kilo

quadrumanus climber

fist-walker

solitary

chimpanzees (african apes)

pan (chimpanzee) - common chimps and bonobos

male: 43-59 kilo

female: 33-45 kilo

gorillas (african apes)

gorilla (gorillas)

lowland and mountain

male: 162-175 kilo

female: 71-98 kilo

humans (homo sapiens)

only living species in nominidae

bipedal - hindlimb

large body size

dinural

brachiator

climber

knuckle-walker

fruit, leaves, meat

solitary, monogamous, polygynous, polygamous

primate heritage seen in humans in:

anatomy, behavior, genes

primate field studies

natural habitat studies

behavioral ecology

study of the evolution of behavior emphasizing the role of ecology factors as agents of natural selection

primate field study information found:

primate behavior

social structure

feeding ecology

ranging patterns

dominance hierarchies (social behavior)

systems of social organization where individuals in a group are ranked relative to one another

- males and females

communication can either be

vocal or non-vocal

vocal communication

"danger"

part of group or not

non-coal communication

displays

scent marking (lemurs)

Home Range (consistent over time)

can overlap between groups

ALL primates have home ranges

Territory

actively defended boundary

within home range and typically includes the core area

conspecifics kept out

some primates are territorial

- costly: active calling; physical aggression

Why have territories if costly?

rare defense

- frugivores (fruit) food limited

- folivores (leaves) food abundant

mate defense

- females rare?

Home range size varies with

availability of food

size of animal

number of group members

cost of group living

competition for food

competition for mates

- sexual selection

increased disease

predators

benefits for group living

predator defense

- dilution effect, selfish herd, more eyes, physical defense

resource defense

- displacement, shared knowledge

female-bonded (types of primate groups)

female kin groups at core

female philopatry

strong female hierarchies

males disperse

common

male-bonded (types of primate groups)

male kin groups at core

male philopatry

females disperse

adult females (moms) helping males with rank

relatively rare (found in chimp)

mothers and infants

form basic social unit in primates

males typically do not participate in rearing offspring

often maintained throughout life

brains and behavior

primates are smart

increased complexity

symbolic thought

communication

behavioral complexity

primate cultural behavior

cultural behavior is learned

learn behavior through observation

tool use (chimp, gorilla, orang-utan)

nut cracking

termite fishing

"spear" use - stabbing vertebrate prey

rain "hats" - leaves

sponges

aggression between groups

protect resources

territoriality

lethal unprovoked aggression between conspecifics occurs in humans and chimps

affiliative behaviors (def)

amicable associations between individuals

Affiliative Behaviors

bonding between individuals

enhance group stability

altruistic behaviors

cooperative behaviors

friendship in baboons