chapter 6 - primates

What are all taxa defined based on

Shared derived traits

5 primitive mammal traits

1. Thermoregulation

2. Tetrapod body plan - four limbs

3. Different life stages - period of growth and development

4. Dichromatism - 2 color vision

5. Heteronym detition - 4 type of teeth

Chordata characteristics

• Notochord provides support and flexibility

• bilateral symmetry

Vertebrata characteristics

• vertebral column

• Presence of cranium

Mammalia characteristics

• mammary glands

• Hair

• 3 ear ossicles (bones)

Eutheria characteristics

• greater placental development

• Live birth

3 Archonta (primate ancestors)

1. Plesiadapiformes (stem primates)

2. Scandentia (tree shrews)

3. Dermoptera (flying lemurs)

5 Primate characteristics

• all primates have mammal traits

1. Opposable thumbs

2. Finger nails and tactile pads

3. Post orbital bar (eye socket bone)

4. Stereoscopic vision (3D)

5. Big brains

Prosimians hands

Has grooming claw on second digit of hind foot but have nails on all other digits

Primate suborder

Strepsirhini (wet nose) and haplorhini (dry nose)

Strepsirrhini : lorises and lemurs traits

Shared derived trait - tooth comb (combined front teeth used for grooming and scraping sap from trees)

• their canines are like incisors and premolars are more like canines

Primitive traits - wet nosed, grooming claw, mostly nocturnal and tapetum lucidum (eyeshine)

Which noses are strepsirrhines and how do you identify ?

A-D: are strepsirrhines since they have a rhinarium

E: is a haplorhin since no rhinarium

• Splits upper nose (midline) and has no hair on it

Haplorhini traits

• clade defined based on loss of rhinarium

Shared derived traits

• loss of rhinarium - flat nose

• Loss of tapetum lucidum - no eyeshine

• Trichromatism - 3 color vision

• Post orbital enclosure

Tarsiers and their derived/primitaive traits

Part of haplorhini And has longest evolutionary history

Primitive

• nocturnal

• Retained grooming claw

• Lack of tooth comb

Derived

• dry nosed (no rhinarium)

Platyrrhini and derived traits

• part of haplorhini and is a new world monkey

Derived traits

• dry nose - nostrils wide and turned outwards

• Mostly dinural - live mostly during day (poly, di, and tri vision)

• Prehensile tail in some (no other primates have)- using tail as arms

How did monkeys get from Africa to South America

Floated and drifted through the ocean.

• monkeys that live in trees, the trees break into the river basically turning into a raft for monkeys to float

• which is why platyrrhini are represented as a single clade (founders effect)

Catarrhini

• part of haplorhini

• Characterized by dry, downward pointing noses and a 2-1-2-3 dental formula

• divides into 2 superfamilies cercopithecodiea (old world monkeys) and hominoidea (apes)

How do apes and old world monkeys differ

Apes have several shared derived traits

• loss of tail

• Distinct “Y5” molar shape

Sub groups and suffixes

Super family -oidea

Family -idae

Subfamily -inae

Tribe -ini

Cladistics of family hominoidea

Family hominidae - great apes

Family hylobatidade - lesser apes

Subfamily - homininae (African ape) and ponginae (orangutans)

Tribes - hominini (humans and chimps) and gorillini (gorillas)

Subtribe - homininia (humans) and panina (chimps and bonobos)

6 forms of locomotion in primates for different taxa

1. Quadrupedalism (most common) - arboreal and terrestrial (leaping using hind limbs) (baboon and howler monkey)

2. Vertical clinging and leaping - body is propelled from one branch to another by hind limbs (tarsier and lemur)

3. Slow climbing - only one limb is moved at a time (loris and orangutan)

4. Brachiation - hand over movement in trees (spider monkey, gibbon and orangutan)

5. Knuckle walking - quadrupedal movement using knuckles and sometimes standing up (chimps and gorilla)

6. Bipedalism - upright walking on hind limbs (humans)

2 skeletal features in primates related to teeth and snout

1. Shortened snout - reduce number of teeth, sense of smell and increase vision

2. Heterodont detition - incisors, canines, premolars and molars

• variety of different teeth to eat and process various foods

• This is generalized mammalian trait

Homodont and heterodont in mammalian detition

Homo - all teeth sinimilar in form, sharp and replaced throughout life

Ex. Sharks

Hetero - different types of teeth for specialized chewing

• one set of deciduous (baby) replaced by diphyodont (adult) as mammal matures

Ex. Humans

4 types of mammal teeth

1. Incisors - cutting teeth front of jaw

2. Canines - long sharp dog teeth (for communication or for hunting)

3. Premolars - more flat teeth

4. Molars - flat chewing teeth

• numbers and patterns of teeth are distinctive for different mammals

Eutherian dental formula

3 incisors, 1 canine, 4 pre molars and 3 molars

• for each side (double it for total teeth)

Formula : 3-1-4-3/3-1-4-3

• number of one side / number of other side

• Incisors - canine - pre molars - molar

Human dental formulae

2-1-2-3 / 2-1-2-3

Specialization in primate teeth

(Idk how this is tested)

Diets and digestive system of primates

Diets - are mostly generalists (eat variety of foods) But depends on size and behaviors

• we’ve adapted to basically every food type available

• Bigger primates rely more on foods that are easily available (ex. Larger primates have to rely on leaves since they never run out)

Given fish, reptiles, birds, mammals and primates and humans, smallest to largest

Reptiles, fish, birds, other mammals, primates and humans

Characteristics related to brain size

Advanced learning ability and advanced social structure

2 theories of primate origins

1. Arboreal theory

• Adapting to living in the forest gave us the traits we know today through adaptations

1. Visual predation theory

• binocular vision, good grasping skills and highly refined eye hand coordination are adaptions for insects hunting in low branches

Behavior

Anything organisms do that involve action in response to stimuli (internal or external)

ex. Responses to environment (conscious or unconscious, mostly unconscious)

Behavioural ecology

Focuses on relationship between behaviours, natural environment and biological traits of species

• has evolved through natural selection

• Behaviours are influenced by genes but they also have abilities to exercise a range of behaviors in any situation (environment)

• Genes DONT code for specific behaviours

Evolution of behaviour genetically and physically

• behaviour constitutes a phenotype and the phenotypes that increase fitness will be able to pass their gene at a faster rate

• Genetic factors limits species ability to learn and have behavioural flexibility

• Natural selection acts on genetic factors shaped by ecological setting of past and present

What behaviour are humans

It’s a primate behaviour, there’s nothing special about our behaviour

HUMAN BEHAVIOUR IS SAME AS PRIAMATE BEHAVIOUR

Primate social structure

Primates are social animals and is one of the major topics in primate research

• broad subject

Is being social a pro or a con as a primate

Very beneficial, aids in predator defense and resource sharing through communication

How did group living evolved

group living evolved as an adaptive response to a number of ecological variable

4 types of Primate social group

1. One male, multi female (baboons and gorillas)

2. Matrilines - females, their daughters and their offsprings. They’re alpha, females choose which males are good enough to mate with them (macaques)

3. Pair bonds - both male and female coparent their offspring, can be permanent or not (humans and gibbons)

4. Multi male, multi female - every individual mate with one another, they have sex with everybody (bonobos)