PRIMATES Flashcards
What is the main diet of primates?
- Most are omnivores
- Some are specialised e.g. leaf eaters
How are leaf eating primates adapted for their diet?
- Specialised stomach in order to digest cellulose
- Use of bacteria and enzymes within the stomach to aid digestion
What are the main body characteristics of primates?
- Retention of clavicle: allows limb movement in all directions
- Elbow joint - rotation of the forearm
- 5 digits on fore and hind-limbs
- Reduced snout and reduced olfactory system
- Reduced number of teeth
- Nails
- Fleshy sensitive pads at the tip of the fingers
Features of primate skull and brain
- Posterior skull (most of the skull is posterior to the orbits)
- Enlarged brain case
- Enlarged cerebral cortex compared to other mammals
Primate eyes
- Forward facing eyes
- Binocular vision
- Depth perception
- Can detect fruits against a background
- Bigger orbits in primates than in other mammals
- Thought the good vision is associated with fruit eating
What benefits comes with having opposable thumbs?
- Increases dexterity
- Allows manipulation of objects
- Moving around trees
Thought that primates evolved from an ancestor that had opposable thumbs for tree climbing
What group are the basal primates in?
Groups of primates
Prosimians (before apes)
Examples of Prosimians?
Groups of primates
Lemurs, bush babies, pottos, tarsiers etc
Features of the Prosimians ?
- Small
- Nocturnal
- Small brains
- Relatively long snout (lemurs)
- Paraphyletic - dry nosed
- Basal primates - branched off early
What group are monkeys and apes in?
Anthropoids
Examples of Anthropoids
?
- New world monkeys
- Old world monkeys - baboons etc
- Lesser apes - gibbons
- Great apes - chimpanzees, gorillas etc
Features of Anthrpoids?
- Mostly larger than prosimians
- Larger brain
- Relatively small olfactory lobes
- Mainly frugivorous or folivorous
- Mostly dinurnal
- Complex social structures
- Different types of locomotion
What is the alternative classification of Prosimians and Anthropoids?
- Strepsirrhini (basal)
- Haplorrhini
Features of Strepsirrhini?
- Small, long snout (rostrum), nocturnal
- 2 halves of lower jaw unfused. Frontal bones unfused
- Lack of orbital septum (hole behind orbit)
- Postorbital bar
- No plate seperating orbits from temportal fossa
Example of strepsirrhini?
Lemur, Loris, pottos, Galagos
Haplorrhini examples
- Tarsiers
- Old world monkeys
- New world monkeys
- Apes
What is the main difference between the 2 ways of classifying primates?
- Prosimians - Anthropoids includes tarsiers along with lemurs etc
- Strepsirhini - Haplorrhini includes tarsiers with NWM, OWM and the Apes.
Haplorrhini skull features
- Relatively short rostrum
- Plate that seperates orbits from temporal fossa
New world monkeys: Features
Haplorrhini
- Platyrrhini (broad-nose)
- 3 premolars (more primitive state)
- Relatively good sense of smell
- Can have prehensile tail
Life history traits of new world monkeys?
Haplorrhini
- Colonised South america from africa - 30mya
- Only arboreal forms - No terrestrial radiation e.g. like baboons
Characteristics of Old world monkeys
Haplorrhini
- Catarrhini (narrow-nosed)
- Nostrils forward and down
- Smaller bone
- Never have a prehensile tail (tails often disappeared)
- 2 premolars
- Trichromatic colour vision - strongly associated with diet
- Poor sense of small - only 50% of olfactory genes are functional
Life history traits of old world monkey examples
Haplorrhini
- Found in Asia and Africa
- OWM are more species rich and specialised
- Colobines - colobus monkeys - leaf eaters - stub thumbed
- Cercopithecines - vervet monkey - short tails, terrestrial - cheek pouches to carry food - longer thumbs but shorter fingers
What are the two groups within old world monkeys?
- Colobines
- Cercopithecines
Characteristics of Apes?
Haplorrhini
- Broader chest
- Scapula position is different - dorsal
- Greater curvature of ribs
- Caudal vertebrae reduced
- Front skull – Characterised by sinuses
- 5 cusps on molars
- Vertebral column altered for locomotion
- Bipedal pose - centre of gravity near vertebral column
The social systems of primates: Female transfer
- Group size: small
- Number of males in group: one or many
- Male behaviour: Territorial (sometimes kinship groups)
- Examples: Chimp, Gorilla, Baboons & Colobus.
Primate Social Systems: Male Transfer
- Groups size: Large
- Number if males in group: One or several
- Male behaviour: Male hierarchy
- Examples: Most Ceropithecines (sub order of OWM).
Primate social systems: Monogamous
- Groups size: One family
- Number if males in group: One
- Male behaviour: Both sexes participate in defence and parental care
- Examples: Gibbons and tamarins
Primate social systems: Solitary
- Groups size: Single (or with offspring)
- Number if males in group: None
- Male behaviour: Range overlaps with range of >1 female
- Examples: Bushbabies and Orangutans
