Lesson 25: Primates Flashcards
social systmes are often driven in part by resource distribution – which in turn the resource distribution drives the ()
ecology –> they influence eachother
behavioral interactions can set you up for ()
competition
often get aloparental care in primates
- care by an individual who is not the direct parent
- infants of high ranking females often derive more benefits from aloparental care than the benefits from infants from lower ranking females
often highly ranked females had more interactions
- raised the notion of being social and raise the benefits of the infant
during social interations can 2 individuals recognize the familiar relationship between eachother
- juvenilles will emit a sound when in peril
- the mother will be the one to respond and other mothers will look at the mother of the screaming baby
where will the losers of conflict often redirect their aggression towards
the relative of the winner –> suggeting awareness of relationships
not easy being the winner
- the stress levels can be chronically elevated partiucularly when the dominace hieratchy is not stable
characteristice of haplorini and the stresurini species
- arboreal
- had complex social systmes
— complex social systems is an ancestral trait to the primates anyway
—- most of these traits can be attributed to the arboreal lifestyle
evolutionary trends: plesiodaptphoria
- ranged from marmot to chipmunk sized
- hypothesized that they went extinct with competion with the rodents
- first primate-like mammal
- nails not claws
strepsirrhini
- small and noctrunal
- wet nose
- all extant species are endemic to madegasgar
lemurs
- ancestor probably rafted over from africa
- since that time they have evolved into their own kind of diversity
- very clearly forms that appear to be arboreal and brachiating
- even ape like diversivication
^^^^ due to their isolation
haplorini
- as a whole are characterized by short snout and also a dry nose
- dienural
- secondarily nocturnal in some
- tarsiiform and tarsier
tarsier
- relatively small brain and huge orbits
- origin from shift from diennural to noctrunal
antrhropoid skull vs. strepsirrhine
- now fused frontal bones in anthropoid
- fused mandibular symphysis in the arthropoud
- anthropoids have larger brains but a small olfactory lobe
– usually dieurnal
– show much more complex social systems
– many traits characterized by their quadrapedial lifestyle - aborality
- suspensary underbranch (swinging)
Catarrhini (old world and apes) traits
- humans don’t habe vumeronasal orans
- have trichromatic vision
- enables detectinon
– red vs. green –> use of fruit within their diet –> fruit is ripe or not - platerines contain 3 premolars
new world monkeys
- appeared in south america (having presumably rafted from africa)
- 3 molars
- aldolids
- no ape-like form like there is with the old world and the lemurs
Catarrhini
- characterized as having more forward, downward pointing nostrils
oldworld monkeys show more derived traits
- gut specialized for fermenting cellulose
– many had a highly specialized form of arborality
trunk of an ape vs. monkey
- monkey;s arms are more rotated in
- our vertebrae evolved as a beam
- in an upright posture, you now have compression foreces
differences (ape v monkey)
one defining characteristics is the presence of culture
- gibbons tend to be more monogamous
- orangutans have 2 species and 2 subspecies
– show extreme forms of sexual dimorphism
– aborality
– use of tools
different forms of walking
- pongo does this kind of fist walking
- but both gorillas and pans(chimpanzee) do what is called knuckle walking
how old are the vertebrates
- life at 4 billion, so about 500 million years old
- modern humans are thought to be at least 200,000 years old (blink of en eye)
homo sapian skull vs pan troglodytes (chimp)
foramen magnum
- point in the back of the skull where vertebrae passes through
- moved from behind the skull to more so underneath the braincase
capacity for bipedalism
- mostly suggested for by hip
lucy + how they knew she was bipedal
- earliest dating homonin?
bipedal - footprints clearly show bipedalism (leaky footprints)
- important becase of the longstanding depate
- bipedalism is necessary for the altricial mode of development in the infant
- bipedalism preceeded the very large brains (very large brains –> had to invest most of every into brain growth – not precocial )
multiple times the human lineages have redistributed themselves
- second move with the homosapitans
- shared the plant with a number of other homo species
- homo erectus persisted for a long period of time
- large and had no climbing traits
ultimate type question
an evolutionary reason
proximate type question
a physiological/functional control basis
changes from the other homo groups
- between the homo sapians and other ancestral groups – the changes aren’t that different from the changes observed in other vertebrates
— how can you deny the relatedness between homo sapians and neanderthals and homo erectus
early brain growth in homo erectus had implications for cognitive ability – human brains are disproportionately large compared to other primates (what drove it??)
proximate
- an individual has a big brain because it is a developmental program and is based on xyz that requires lots of nutrients – most expensive organ in the body
ultimate
- ex: increasing cognitive ability was adaptive because….
evolution of cooking is a theory for how we got this large brain
- they would not have had such large brains early on
- cooking makes the assimilation of energy in food much more easily attainable
- presumably reduces disease risk
- the energy content isn’t greater – but because it has been changed, the energy is more accessible to the body
- the energy is now there to support the large brain growth
cooking
the permanent transformation of food through the application of heat
even homo erectus did not have as large of a brain as homo sapians
by age 8, already at 90 percent of brain growth
- far less altricial than modern day human develop,ent
neanderthals
- we think that they might have had even a larger brain size than modern day humans
- had very large occipital lobes
- buied their dead
- divergence between neanderthals and modern day humans about 500,000 years ago
origin of modern humans (homo sapians)
- humans that are visibly indistinguishable than us today
- can trace DNA back to one woman in africa
—-> called her eve
—–> only one lineage that survived long enough to produce the diversity we have today
– mitochondrial DNA is passed down from mother
when did the first bipedalism evolve
- about 4 and a half to 7 million years ago
- lucy
- evolved bipedalism in the trees
- savahhanah hasn’t even evolved yet (no tall grass to see predators over)
if you are not bipedal, then it is much more liekly that your offspring are
much more precocial
– able to cling to mother’s fur and hang on
bipedalism evolved first to enable
altricil care
2 generations of teeth
- needed lactation
- large brain
human foot
does not have a diverging toe
bipedalism has made us excellent for long distance running
- efficient in running
- ^^^ also could have been a driving point of how bipedalism came to be
- humans are really good at sweating – do not experience that heat exhaustion that easily
change in thorax area in homo sapians
- something evolved – change in the thorax region
- ventral shift of the larynx which allowed for a large resonating chamber – makes it possible to make long vowel sounds
SIDS
– could be caused by this
^^ enables us to breathe through mouth instead of nose
^^ shift saved lives
- ## may have been driven by evolution of the cold virus –> could have been driven by the evolution of languge
