Primates Flashcards
How does homology aid us in the study of primates?
Shared traits acquired by a common ancestor. Gives more insight into anatomy and behaviour of ancestors through living primates, as opposed to others eg. reptiles.
How does analogy aid us in the study of primates?
We can see how evolution shapes adaptations in response to different selection pressures.
How do primates reflect the ‘mosaic nature of evolution’?
As primates were spread across nations, 50-60mya, and faced different environmental and selective pressures they have evolved different and not in a linear fashion.
What are ancestral traits shared between primates and humans?
Ancestral traits are those inherited from a common ancestor eg. being vertebrates, homeothermic, and having hair
What are derived traits?
Newly arising traits, one that a current organism has, and a previous one didn’t
What are some distinguishing traits of primates?
Prehensile hands, opposable big toes, stereoscopic vision, reduced olfactory reliance, nails, unspecialised teeth, large brain, small litter size, and prolonged dependency of young.
However, none of these are unique to primates and not all primates possess these.
What are some examples of human traits being different from that of the distinguishing traits of primates?
Prehensile hands and feet; out feet aren’t - bipedality
Opposable big toes; we don’t grasp with our toes…
Stereoscopic vision; We have binocular (overlapping), eyes rotated to front to see in 3D and colourful vision
What are some examples of distinguishing traits of primates being shared with human traits?
Reduced olfactory reliance; Increased reliance on vision
Nails v claws; nails to protect sensitive skin on fingers and toes
Unspecialised teeth; Not needed for warfare or dietary reqs.
What are the different group of primates?
Prosimi, Tarsioidea, Anthropoidea
What are some distinguishing traits of prosimians?
PO Bar only
Wet nose and split lip
Dental comb
What are two examples of prosimians and their distinguishing traits?
Lemurs (Madagascar): Underwent adaptive radiation (complete isolation from primates elsewhere), lower body temp and metab rate to survive extreme dietary reqs.
Ring-tailed lemur: Highly gregarious, greater reliance on vision yet still high reliance on olfactory system, scent mark vegetation and scent mark tails for territory.
What are some distinguishing traits of tarsioids?
PO bar and partial plate
Dental formula 2133/1133
Elongated tarsal bones of foot
What are some distinguishing traits of Anthropoids?
PO bar and plate
Nails on all digits
What are some distinguishing traits of the platyrrhini infraorder?
Flat nose
Widely separated nostrils
Found in South and Central America
What is the extant superfamily in the infraorder platyrrhini? and some distinguishing traits
Cebidae (capuchins); Relatively large body sizes, live socially with varied diet, have culture and traditions.
What are the two extant superfamilies in the infraorder catarrhini?
Cercopithecoidea and hominoidea
What are some distinguishing traits of the cercopithecoidea superfamily?
Nostrils close together
Non-prehensile tail
Bilophodont molars
What are some distinguishing traits of the Hominoidea superfamily?
Tail absent
Antero/posteriorly flattened thorax
Some Y-5 Molars
What are the three families of the Hominoidea superfamily?
Hylobatidae, pongidae, and hominidae
What is the distinguishing trait of the hylobatidae family?
Gibbons; Brachiation as main method of locomotion
What are some distinguishing traits of the pongidae family?
There are no unique traits.
Gorilla; fist or knuckle walking, sparse body hair, found in borneo and sumatra, quadrumanous
What are some distinguishing traits of the hominidae family?
Humans; Knuckle walking or bipedal, mixed sex communities
What is behavioural ecology?
Why different species behave in different ways. A product of natural selection resulting in increased adaptation to ones habitat.
What is the effect of socioecology on behaviour?
Ones social system is the response to ecological conditions; availability and distribution of resources
Effect of survival fitness on behaviour?
There is a suite of adaptations to the ecological and social environment; food, co-ordinate male, offspring, avoiding parasites and predators
What are the costs and benefits of large groups?
Benefits: Lower risk of predation (safety in numbers) and better defence of territory
Costs: Increased comp for resources, increased likelihood of disease, and increased conspicuousness
How is the optimal group size achieved?
Size reflects the balance of costs and benefits; influenced by social and ecological factors
Female #’s are limited by food due to high metabolic costs of gestation and lactation
Male #’s are limited by # of females
Ecological pressures influence distribution of females and males distribute themselves to maximise access to females
What is the relationship between specialisations and diet?
Dietary specialisations drive other specialisations such as teeth and body size.
Insectivores are smaller than frugivores while are smaller than folivores; differences in size related to differences in energy reqs
What are some specalisations of primates than have come about as a result of their diet?
Digestive tract; primates are unable to digest cellulose, and as a result have developed a digestive tract with a microorganism present to digest cellulose
Brain size; frugivore larger than folivore. Need to remember location and phenological status of fruit trees
Is there a link between the distribution of resources and territoriality?
Yes
Clumped resources; ability to be defended hence high territoriality
Even distribution; egalitarian relationship, difficult to defence
What are three types of group distributions? and what is their purpose
Scramble; in an even distribution of resources, as the amount of food per individual is inversely proportional to group size
Contest; found in clumped resource distributions, aggressive competition over defensible resources
Fission-fusion; split into sub-groups to later reform, unequally dispersed food, used to reduce food competition through dispersal of small foraging groups
What are some types of primate social organisation?
Solitary
Pair-bonded
Polyandry (one female)
Polygyny (one male)
Polygynandrous (multi-male)
What is a solitary social organisation?
Galago or orangutan
Males defend home ranges that ecompass home ranges of several females
What is pair-bonded (monogamy) social organisation?
Gibbons
Females are dispersed and males associate with one
Often territorial
What is a polyandrous social organisation?
Marmoset, callitrichids
Several males associate with one female
What is a polygynous social organisation?
Gorilla
Resident male monopolises reproduction to increase their own reproductive success
Often leads to infanticide; new male kills all offspring not related to him
What is a polygynandrous social organisation?
Baboons and Chimpanzees
Multiple males and females. Often fission-fusion. Often promiscuous - >1 partner to increase reproductive success
Is there a correlation between sexual dimorphism and polygyny?
Pronounced body dimorphism is suggestive of high male-male competition
Gibbons are monogamous; male canine = female canine
Gorillas are polygynous; substantial dimorphism in canine length
Humans have mild polygyny; less dimorphic than pre-homo fossil hominins
Is there a relationship between testis size and mating system?
Yes
Promiscuous mating have much larger testes than single male groups. Competition over mates and sperm competition.
