lecture 9: Primate adaptations

4 main areas of adaptation

1) locomotion
2) Digestive system
3) sensory system
4) social system

7 basic types of locomotion

1. tree shrew(pre primate) moves quickly on all 4s in all directions
2.leaping (prosimians)
3.quadrupeds(long and narrow trunks)
4. semi brachiators(spider monkey use arms to swing)
5.Brachiation
6.knuckle-walking
7. habitual biped(humans)

most primates have adapted a digestive system and diet of\_______

omnivores

specialist adaptation

narrow niche with few habitats and can go extinct easily because cannot adapt

generalist species

Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples are flies, cockroaches, mice, rats, and human beings.

exoskeleton

hard protective structure developed outside the body of insects(made of chitinous exterior)

sensory system

part of the nervous system that detects or senses the environment

primary sensory system in primates

vision

stereoscopic vision

the ability to determine an object's depth based on that object's projections to each eye

evolution of stereoscopic vision caused changes in what body part in primates?

early primates have a somewhat reduced snout and late primates have small noses and almost no snout

Opposable big toes in primates

all primates have opposable toes EXCEPT humans

opposable thumbs

thumb that enables grasping objects and using tools. ALL primates have

how did sense of smell evolve in primates(brain change)

Olfactory bulb got smaller

social systems

how an animal relates to others of its same species

6 basic types of primitive social behavior

1) Noyau
2)territorial pairs
3)1 male group (harem)
4) multi-male group
5) Harem
6) Chimpanzee behavior

Noyau social group

multiple non-overlapping female territories with one overlapping male range (each lead solitary lives)

noyau social groups are among which primates?

nocturnal,insectivorous prosimians (lorises) and Orangutans

territorial pairs

monogamous. (gibbon, siamang)

1 male group (Harem) social structure

consists of one adult male, several females and their offspring

complementary groups of harems

groups of all male bachelors

what is the most common form of primate social organization?

1 male groups(harems)

multi-male groups

- males compete for dominance rank
- males twice as big as females
- male dominance rank is function of size and strength
- high ranking males has greater access to females

what is the important evolutionary development that comes from a multi-male group?

Males learn to live together and cooperate
-development of submissive males

harem within a multi male social group

Uncommon;
Each male has own Harem;
Males do not fight each other for females, but females choose which males/groups they want;
Allows strong male/female bonds & multi male relationships;
Several groups can split off for foraging which permits more effective exploitation of environment

chimpanzee social behavior

-closest to humans
-change in dominance rank is rarely violent and depends more on the size of the display
-females choose whom they want to mate with

Hedonistic behavior

to reassure each other to a great extent
-touchy-feely behaviour