Lecture 8 - Oligocene & Miocene

Question 1

Miocene

early Miocene faunal trend

Answer 1

faunal exhange between Africa and Asia

Question 2

miocene

climate optimum

Answer 2

17-15 Ma
- widespread forests
- apes diversify and leave Africa

Question 3

Miocene

result of Africa island isolation

Answer 3

• endemic fauna = not found elsewhere
• very diverse fauna, more than today
• Afrotheria - group of animals that evolved in Africa when it was isolated from the world (elephants, elephant shrews, sea cows, hyraxes)

Question 4

miocene

what happened 17.3 - 16.4 Ma

Answer 4

• land bridge that connected Africa to Eurasia
• asymmetric exchange of animals –> more came into Africa than left
• elephants particularly successful - spread all over the world

Question 5

grasslands in NA

when, how, results

Answer 5

latter half of Miocene, trend of aridification (drying out)
- resulted in climate driven evolution –> coev of horses and expanding grasslands

Question 6

grasslands in NA

early horse ancestor traits

Answer 6

• lived in forest/tropical settings
• ate soft/pulpy vegetation
• did not have cursorial adaptations (to run fast)

Question 7

grasslands in NA

cursorial adaptations

Answer 7

to run extremely fast
- when living in open settings, visile to predators so prey has developed cursorial adaptations

Question 8

grasslands in NA

horse adaptation to grasslands

Answer 8

long legs
one toe
higher teeth - hypsodonty

Question 9

grasslands in NA

what is hyposdonty

Answer 9

• linked to open habitat grazing
• many groups have developed –> suids, rhinos, equids, marsupials, sloths, rodents
• suited for extremely abrasive diets that can be worn down

Question 10

grasslands in NA

structure of hypsodontic tooth

Answer 10

dentine & cementum - fill in btwn enamel but are softed
- chop grass pieces btwn enamel
- enamel wears, but still able to use them

Question 11

grasslands in NA - hypsodonty

why do grazers wear teeth

Answer 11

silica phytolithis
- grasses contain cell structures made of silica (biogenic opal) called phytoliths, internal grit
- more abundant in grasses than in leaves

dust
- covers grass, external grit

Question 12

rise of grasslands in Africa

Answer 12

begins around 10 Ma and progresses towards end of Miocene
- important implications for human resources –> little shelter or food resources

Question 13

miocene apes

primate adaptations

Answer 13

• arboreal & terrestrial quadrapedal
• clinging and leaping
• suspensory locomotion

Question 14

miocene apes

proconsul/ekembo

Answer 14

Kenya, Uganda - 25-23 Ma
- above branched quadraped, monkey-like in general lifestyles
- no tail & dental anatomy points towards ape relatives, but acted like apes

Question 15

miocene apes

dryopithecus

Answer 15

Europe - middle to late Miocene
- more suspensory adaptation

Question 16

miocene apes

Sivapithecus

Answer 16

India & Pakistan - 12-7 Ma
- cranially looks like orangutan
- doesn’t show postcranial specializations for suspension

Question 17

living apes - Hominoidea

current living apes and where

Answer 17

orangutans - indonesia
gorillas - tropical africa
chimps & bonobos - tropical africa
gibbons & siamangs - tropical SE asia
humans

Question 18

living apes - Hominoidea

where & when do earliest apes occur

Answer 18

Africa - 25 Ma: Proconsul
faunal exchange between Africa & Eurasia
- hundreds of sites in Eurasia that preserves apes from Miocene

Question 19

living apes - Hominoidea

comparison to modern apes

Answer 19

• cranial adaptations modern ape like
• postcranial adaptations not ape-like
• extremely suspensory locomotion not until end of Miocene
• hyperdiverse, all over the globe

Question 20

living apes - Hominoidea

monkeys/cercopithecoids, now vs Miocene

Answer 20

now: hyperdiverse, all over globe
miocene - opposite of now, only couple of early monkeys

monkeys appear in late Oligocene/ early Miocene but don’y diversify until Pliocene

Question 21

living apes - Hominoidea

apes vs monkey diversification

Answer 21

apes are adapted to moist, tropical environments
monkeys are much more successful in open, dry environments
- apes hold onto the same places today (less diverse)

Question 22

class paper

koch 1998

Answer 22

isotopic analysis (using OCN) of teeth and bones reflects various aspects of an animal’s diet, water intake, and habitat