Primates Flashcards
homology
close relatives share similar traits due to common ancestory
phylogenetic constraints
evolutionary history limits the variations observed in current populations/species
vestigial traits
‘legacies’ from ancestors that are not functional at present
convergence
traits of unrelated or more distantly related groups appear similar due to common selective pressures - rather than common ancestors (analogous/homoplastic traits)
examples of humans an primates being similar (4) (4)
- warfare
- culture and traditions, west african chimpanezes using hammers
- prosocial behaviour (caring about the welfare of someone else)
main reasons for studying primates reasoning by homology (4)
Closely related species tend to
be similar morphologically
because they share traits
acquired through descent
from a common ancestor
› studies of living primates
often give us more insight
into the anatomy and
behaviour of our ancestors
than do studies of other
organisms
main reasons for studying primates reasoning by analogy (4)
Natural selection leads to similar
organisms in similar
environments > by assessing
the diversity in the behaviour
and morphology of organisms in
relation to their environments,
we can see how evolution
shapes adaptation in response
to different selective pressures
clade (4)
clade = radiated from a single ancestory
ancestral traits in the order primates (4) (4)
- vertebrae (all vertebrates)
- homothermic (includes birds + mammals)
- hair and mammary glands (mammals)
- arboreal & nocturnal (insectivora = close order to primates)
derived and ancestral meaning (4)
ancestral = retained from ancestral groups
derived = newly arising in focal taxon
ancestral (primitive) traits of primates (4)
- insectivore
- arboreal
- nocturnal
primate derived traits related to arboreal lifestyle (4) (4)
- prehensile (grasping) hands/feet
- opposable big toe
- stereoscopic vision (forward facing orbits
- Olfactory (smelling) apparatus reduced
- Nails (versus claws)
- Unspecialised teeth
- Relatively large brain (relative to body size)
- Small litter size (most usually have 1 baby at a time)
- Prolonged dependency of young
BUT:
- None of them makes primates unique
- Not every primate possesses all of these traits-
binocular vision (4)
fields of vision of the 2 eyes overlap so that both eyes perceive the
same image
steroscopic vision (4)
= each eye sends a signal of the visual
image to both hemispheres in
the brain to create an image
with depth
color vision (4)
all diurnal primates have it,
nocturnal primates don’t
prosimii vs anthropoidea (4)
anthropoidea = postorbital plate
prosimii = postorbital bar
olfactory apparatus is reduced in primates (4)
decreased reliance on sense of smell
(olfaction) -> reduction in sensory areas of brain and in snout
- especially in diurnal primates
primates in general have nails, non-primates have claws
unspecicalised teeth (4) (4)
- utility
- processing food
- weapons in conflicts
- Primates have generalized
dentition - Teeth tell us something about
- dietary preferences
- age of individuals and
developmental patterns - phylogenetic relationships
- social structure
dental formula in humans
top jaw/ lower jaw on one side of mandible
2123
2 incisors
1 canine
2 premolars
3 molars
what does the 2123 dental formula do
2123 distinguishes an old world primate from a new world primate
relatively large brain (4)
- Primates generally
evolved larger body size - Brain increases with
increase in body size - Primate brains
increased in size more
rapidly than body size
(4)
Modes of locomotion
Vertical clinging and leaping
Quadrupedalism
Brachiation
Bipedalism
Dentition & diet
Tooth form, differentiation, size, enamel
Sexual dimorphism in canines
Diet (insects, fruit, leaves, seeds & tubers, meat)
Sociality
Solitary
Monogamous pairs
Polyandry
~ Polygyny
Brain development
Large relative to body size compared to other mammals
Hominids relatively larger still
prosimians
Prosimii (‘before monkeys”)
Earliest primate group 55+ MYA
- More reliance on olfaction
- long snout
- moist, fleshy pad (rhinarium) at
end of nose
use scent marking
- “split” upper lip
- Dental comb
- Unfused mandible (lower iaw bones)
- Dental formula most 2133/2133
- Post orbital bar, not plate
- Many nocturnal
- Tapetum lucidum
reflective layer in eye that
maximizes use of light
Quadrupedal & mostly arboreal
Prosimii: Lorisoidea (4)
2 families
- Lorises (Lorisisdae)
- Galagos (Galagidae)
Africa and SE Asia
2133/2133
Quadrupedal climbers
Nocturnal, arboreal,
solitary
Leave their dependent
offspring in nests
Family: Galagidae: Galago spp.
(Galagos or bush babies)
Continental Africa
Long bushy tails
Large ear pinna
Nocturnal
Leapers
Prosimii: Lemuroidea,
Family: Lemuridae
Madagascar
Diverse taxon
Most nocturnal
Most arboreal
Some torpor
state of decreased
physiological activity
Females dominant
Lemuridae: Lemur catta
(Ring-tailed Lemur)
Madagascar
* 3 kg
* Diurnal, partly terrestrial
* Social
* Scent mark vegetation
* Males display waving
‘scented’ tails (‘stink
fight’)
Lemuroidea: Indridae:
Indri indri (Indri)
Madagascar
* Diurnal, arboreal
* Ca 7 kg
* Vertical clinging & leaping
what is the Tarsioidea
Tarsioidea: Intermediate
to Prosimii &
Anthropoidea
Anthropoidea vs Prosimii
Anthropoidea = postorbital plate
Prosimii = postorbital bar
Tarsioidea
East Asia
* Nocturnal and arboreal
* 110 grams
* Dental formula 2133/
1133
* Diet: 100% animal prey
* Incomplete postorbital plate
* Grooming claws (2)
* Eye larger than brain
* Rotate head almost 180
degrees
* Clinging and leaping
* Solitary (except females +
young)
Anthropoidea: New World & Old World Monkeys & Apes
Single clade (all from
one ancestor)
* No grooming claw (all
nails)
* No tapetum lucidum
* Largely diurnal
* Fused lower jaw
* Short snout / reduced
olfactory reliance
* Postorbital plate
* Larger relative brain size
than prosimians
Platyrrhini (‘flat noses’):
Ceboidea (New World Monkeys
/ American Monkeys)
Only Ceboidea (but not all) have
prehensile (grasping) tails
* Dental usually 2133/2133
* Sideways-facing nares (nostrils)
* Completely arboreal
* Diurnal (except 1 genus)
* Two large families – Cebidae – Callitrichidae
* reduced body size
* 2132/2132
Ceboidea: Cebidae
Diverse family
* Dental 2133/2133
* >3-8 kg
* All nails
* Many with
prehensile tail
* Diurnal
* Social
* Leaves, fruit,
animal matter
Capuchin monkeys (Cebus & Sapajus spp.)
Social conventions (traditions) Tool use
Ceboidea: Callitrichidae
All <1 kg
* Dental = 2132/2132
(molar reduction!)
* Claw-like nails (reversal)
except 1st toe
* Diurnal
* Diet: fruit, gum, animal
* Family groups of 5-10
* Most twin
Catarrhini (‘narrow noses’):
Cercopithecoidea (Old World
Monkeys)
1 family (Cercopithecidae) = Old
World monkeys
* Dental: 2123/2123
* Bilophodont molars
* Ischial callosities near tail
* Some with sexual swellings
* Tail never prehensile
* Wide variety of habitats
* 2 subfamilies
* Cercopithecinae – largely fruit eating
* Colobinae – largely leaf eating
Subfamily
Colobinae
Africa, Asia
* Arboreal (most)
* Leaf and seed eaters,
lichen (some)
* Have complex stomachs
* Often found in ‘harems’
Subfamily
Cercopithecinae
Africa & Asia
* Variable in size
* Typically live in medium or
large bisexual groups
(multimale-multifemale)
Examples of Cercopithecinae
Mandrill (Mandrillus
)
* Most brightly coloured
mammal
* Lives in supergroups,
sometimes exceeding 1000
Catarrhini: Hominoidea
(Apes and Humans
)
- Larger body (usually)
- No tails
- Limb arrangement reflecting
brachiation
– rotation of shoulder & scapula
– ventral-dorsal flattening of trunk
(shallow chest)
– wrist joint flexibility - Longer forelimb than hindlimb
– human reversal - Y-5 molars on mandible
- Relatively even larger brains
- Prolonged dependency of young
Hominoidea:
Hylobatidae (Gibbons)
- SE Asia
- Diurnal, arboreal
- 6-8 kg
- Brachiators
- Ischial callosities
- Monomorphic body size
(but some dichromatism) - Mostly fruit
- Monogamous
- Territorial
- Vocal duets
Hominoidea: Pongidae
(Orangutans)
Orangutan (Pongo
)
– 2 species
* Borneo & Sumatra
* Ca 37-77 kg
* Males 2x female body weight
* No ischial callosities
* Quadrumanous
* Cheek flanges in dominant males
* Diurnal, arboreal
* Most solitary
* Slowest life history of all primates
– age at first reproduction: 15 yrs
– inter-birth interval: 9 yrs
Hominoidea:
Hominidae (African
Apes & Humans)
Gorilla (Gorilla)
* 70-170 kg; males = 2x
females
* No ischial callosities
* Knuckle walk
* More terrestrial
* Mainly folivorous
* Typically in one-male
groups
Hominoidea:
Hominidae
2 species – chimpanzee – bonobo
* 31-60 kg
* Knuckle walk
* Quadruped;
climbing
* Fruit, leaves,
animals
Behavioural peculiarities of chimps andx. bonobos
Large mixed sex communities
– female chimps disperse from their natal
groups when they reach maturity; males
remain in their natal groups
– members of the community are rarely found
together in a unified group; they split up into
smaller parties (fission-fusion)
– in chimps, the strongest social bonds are
formed among males; in bonobos females
form stronger bonds with their adult sons
* Chimps modify natural objects for use as tool in
the wild
* Chimps co-operatively hunt other primates
* Bonobos: ‘make love not war’ ape
– sex eases tension between individuals & may
allow them to feed near one another without
undue stress
Behavioural ecology
Behavioural ecology: the
study of behaviour from an
evolutionary and ecological
perspective
