Primates Flashcards
1
Q
Order: Primates
A
- 4th largest order of mammals (after rodents, bats and insectivores)
- includes great apes, humans
- more than 250 species
- most arboreal (live in trees)
2
Q
Features of primates:
- Plantigrade feet
A
- most mammals walk on tips of the feet (on their toes) = digitigrade
- Primates walk on their entire feet right up to the heel = plantigrade
- other plantigrade mammals = bears, hedgehogs
3
Q
Features of primates:
- Grasping digits
A
- Primates have prehensile (grabbing) digits and opposable thumbs
- finger nails, not claws
- adaptation for arborela existence
- important in evolution of tool use
4
Q
Features of primates:
- Binocular vision
A
- forward facing eyes
- often enormous
- increased visual sense (including colour vision) at the expense of sense of smell
- Adaptation for:
- nocturnal existence
- judging distances
5
Q
Features of primates:
- Increased brain size
A
- particularly in great apes and humans
- visual and locomotory areas greatly enlarged
6
Q
Features of primates:
- Shoulder anatomy
A
- a well developed clavicle (collar bone)
- very flexible rotating shoulder joint
- good for movement through trees
7
Q
Features of primates:
- Upright posture
A
- most primates can sit upright
- some can walk short distance on hind legs
- humans do it habitually
8
Q
How do humans differ from other great apes?
- Locomotion
A
- bipedalism - humans walk upright habitually
- great apes typically ‘knuckle walk’
- human foot become less grasping - big toe straightened
9
Q
Skeletal differences associated with upright walking
A
- big toe redued
- pelvis shortened, more bowl-like than blade-like (helps support base of spine)
- femur bends inwards, knee straightened, patella central to joint
- conneciton with spinal column (foramen magnus) on underside of skull
- less robust upper arms
10
Q
Consequence of upright walking
A
- freed hands for other purposes
- greater manual dexterity
- greater tool use
- ability to throw accurately (important in hunting)
11
Q
How do humans differ from other great apes?
- Diet
A
- humans are highly omnivorous, but with a much higher meat intake than other apes
- also eat higher amount of processed food e.g. cooked, pickled, fermented
12
Q
How do humans differ from other great apes?
- Brain size
A
- humans have a greatly increased brain size compared to our nearest relative
13
Q
Where did hominids originate?
A
- majority of hominid fossils found in East Africa
- most of these in sites in the Rift Valley
- Lots of lakes and human fossils found in same deposits as lake dwelling creatures e.g. fossil hippos
- early hominids must have spent some time around water
14
Q
Hominid diversity and evolutionary tree
A
- About 20 species
- 3 main genera:
- Australopithecus (about 7 species)
- Paranthropus (3 species)
- Homo (about 7 species)
15
Q
Sahelanthropus tchadensis
A
- First hominid?
- discovered 2001 in Chad
- nicknamed “Toumai”
- 6 to 7 million years old - chimps and humans may have common ancestor earlier than thought
- skull only
- location of foramen magnum on base of skull, suggests it was bipedal
16
Q
Australopithecus afarensis - “Lucy”
A
- lived 3-4 mya
- skeleton includes jawbone, part of pelvis and entire femur
- enables great interpretation of the way it lived
- first solid evidence for the transition from four to two legs = bipedalism
17
Q
A. afarensis walked upright - Evidence 1
A
- shape of pelvis very similar to modern humans
18
Q
A. afarensis walked upright - Evidence 2
A
- angle of femur and articulation with knee joint indicates bipedalism
- bones suggest A.afarensis only 1.2m tall
19
Q
A. afarensis walked upright - Evidence 3
A
- discovery of tracks in volcanic ash (3.5 mya) - walking on two feet
- A. afarensis jaw bone found nearby
- Footprints are heel to toe - walking like humans
- two individuals (parent and child?) walking side by side
- animal walking next to them?
20
Q
Was Australopithecus afarensis brainy?
A
- Facial features more chimp-like
- Complete juvenile skull - 3.3 myo suggests more human appearance (but chimp dentition)
- adult cranial capacity = 440ml (comparable with chimp)
- no increase in brain size in Australopithecus
21
Q
The earliest ‘humans’ - the appearance of Homo
A
- the earliest species of Homo was likely Homo Hability (‘handy man’)
- H. habilis lived from 2.5-1.5 mya
- often found with simple stone tools
- cranial capacity = 600ml (larger than chimps and Australopithecus but still much smaller than modern humans)
22
Q
Humans begin to travel the world: Homo erectus
A
- Lived 1.8 my - 300,000 ya
- more complex stone tools
- increased cranial capacity:
- 900ml (early specimens)
- 1100ml (later specimens)
- built simple dwellings
- used fire 300,000 ya
23
Q
When did Homo sapiens appear?
A
- first Homo sapiens fossil appear between 190-160,000 ya
- Nicknamed ‘Omo I’ found by the Omo River, Ethiopia
- Cranial capacity = 1300ml
24
Q
Neanderthals - Homo neanderthalis
A
- nearest relative of Homo sapiens
- lived between 130,000 - 30,000 ya
- found in europe and middle east
- very similar societies to Homo sapiens (hunter/gatherer)
- may have been out-competed by Homo sapiens (or may have interbred?)
- Shared up to 99.5% of genes
25
Q
Homo floresiensis
A
- discovered in 2004, on Flores, Indonesia
- VERY recent (18,000 years old)
- thought to have descended from Homo erectus ancestor
- tiny skull and skeleton hence nicknmed the ‘hobbit’
