Ch 6 Overview of the Primates Flashcards Preview

Anth 1026 > Ch 6 Overview of the Primates > Flashcards

Flashcards in Ch 6 Overview of the Primates Deck (24)
Loading flashcards...


"The attribution of human characteristics or behaviour to a god, animal, or object "
- In science, anthropomorphism equated with a lack of objectivity
- Has been really influential in discrediting some arguments
- Do not assume animals share any of the same mental, social, and emotional capacities of humans; rely on strictly observable evidence


Why Study Primates?

- Helps compare ourselves with our closest living relatives
• Can use their behaviour to make suggestions about our behaviour
• Can use it to make hypothesis
- To compare anatomy and behaviour
- To explain selective or random factors impact on behavioural and physiological systems


Defining a Primate:
Class, similarities

Class: Mammalia
- Member of the placental subcategory (not egg-laying or marsupial subcategories)
Other Placental Mammals
Similarities include
• Body hair, mammary glands, heterodonty
• Increased brain size, capacity for learning, behavioural flexibility
• Long gestation period, live birth
• Thermoregulation


Primates as Generalists

Makes the group hard to define
- Big reason for our and their success
- Lack specialized features
• No single characteristic that distinguishes them from other orders of mammals


General Characteristics:
#, location, size range

- 300 primate species identified: Living and non-living
- Most in tropics, sub-tropics
- Great range in size
• Pygmy Mouse Lemur 30g
• Gorilla 200kg
• Gigantopithecus blacki (extinct) maybe 600kg


4 Main Characteristics

1. Locomotion
2. Sensory adaptations
3. Dietary adaptations
4. Behaviour


Locomotory Features

- Generalized skeletal structure: upright, flexible shoulder joints
- Grasping hands
- Opposable thumbs
- Grasping feet (opposable big toe)
- Nails instead of claws
- Flattened nail with tactile pad


Sensory Adaptations

- Colour vision (except nocturnal primates)
- Depth perception-
• Forward facing eyes
• Overlapping fields of view
• Decreased reliance on smell
- Reduction in snout size (rostrum) and olfactory areas of brain


Sensory Adaptations:
Bony orbit in prosimians vs. monkeys, apes and humans

- Enclosed bony orbit
• Evolved for protection
- Post-orbital bar in prosimians (not monkeys and apes)
- Post-orbital plate or cup in monkeys, apes, humans


Dietary Adaptations

- Primate Teeth reflect omnivorous diet
- Lack of dietary specialization
• Not herbivores or carnivores


Dietary Adaptations:

Diphyodont – two sets of teeth, ‘baby’ and ‘adult’
Heterodont – different kinds of teeth (incisors, canines, premolars, molars)
- Primates have fewer teeth than other mammals


Behavioural Features

- Larger brains, especially neocortex
- Controls for higher functions
- Greater facial expressiveness
- Greater vocal repertoire


Behavioural Features:
Reproduction and Nurturing

- Longer gestation period & lower reproductive rate
- K-selection
• Fewer offspring
• Single births the norm
• Greater investment of parental care to improve survival odds
- Long period of offspring dependency


Middle Ear

Petrosal bulla
- Bony casing of a bony plate in middle ear
- Separates middle ear region from interior of skull
- Can be detected in fossil primates
- Maybe this is the trait that will always distinguish other mammals from primates??


The Origin of Primate Characteristics:
Arboreal Hypothesis

"Forward-facing eyes, grasping hands, nails instead of claws all evolved as adaptation to an arboreal way of life"
Why has it never been accepted?
• There are other mammals that are very well adapted to living in trees (squirrels) that do not possess similar traits to us


The Origin of Primate Characteristics:
Visual Predation Hypothesis

"Forward facing eyes and grasping hands evolved as adaptations to hunting insects"
The flies would be moving around a lot so that’s where depth perception comes in, need to be able to grasp them; so thumbs
Why has it never been accepted?
- Not many have a diet that’s high in insets, not something that’s SO important in their diet that it would have caused this


The Origin of Primate Characteristics:
Angiosperm Radiation Hypothesis

"Primate characteristics evolved as adaptations to a diet of flowers, nectar, berries and seeds"
Why has it never been accepted?
- Does not explain stereoscopic vision, or why molar teeth dissimilar to molars
of known nectar eating species
- The known mammal species that have diets high in nectar don't have the same teeth


Foliovores, Frugivores, Insectivores

Will favour one food over others
Some have developed specialized gastrointestinal tracts to eat mostly leaves
Foliovores – leaf-eating
- Ex. colobus monkey specialized digestive system
Frugivores – fruit-eating
- Most common
Insectivores – insect-eating
- Many strepsirhines



- Some primates occasionally kill, and eat birds, amphibians, and small mammals
- Even if they hunt there's no way it counts as their diet because it’s not very important (in terms of daily caloric intake)



4 kinds of teeth for varied diet:
- Incisors
- Canines
- Premolars
- Molars
**Old world Monkeys and Apes
**New Works Monkeys



- Quadrupedal
- All have long arms (longer than legs)
- Brachiation- arm swinging locomotion


Knuckle Walkers

- Longer arms than legs
- Chimps and gorillas


Vertical Clinging and Leaping

- Mostly the same length arms and legs
- Many lemurs & tarsiers



- Arm-over-arm movement
- Gibbons, siamangs
- Semi-brachiators – some NW monkeys