Slides 29

Question 1

derived characters of mammals

Answer 1

mammary glands which produce milk to feed young, hair and fat layer under skin for insulation, kidneys which conserve water from wastes, endothermy (warm-blooded) and high metabolic rate, efficient respiratory system and circulatory systems, large brain-to-body ratio, extensive parental care, teeth modified for shearing, crushing, or grinding

Question 2

early evolution of mammals- synapsids

Answer 2

amniotes that include mammals; early lacked hair, had sprawling gait, laid egg; distinguished by single temporal fenestra (hole behind eye socket)

Question 3

early evolution of mammals- jaw

Answer 3

new jaw joint formed between the dentary and squamosal bones, became incorporated into middle ear, transmit sound from ear drum to middle ear

Question 4

mammal evolution

Answer 4

synapids by end of Triassic period, true mammals during Jurassic, radiated with loss of dinos!! open niches

Question 5

major lineages of mammals

Answer 5

monotremes, marsupials, eutherians

Question 6

monotremes

Answer 6

egg-laying mammals, only in Australia and New Guinea, four species of echidnas and platypus, lack nipples and secrete mile from glands on bellies

Question 7

marsupials

Answer 7

share derived traits with eutherians, higher metabolic rates, nipples to provide milk, birth of live young, embryonic development in uterus, placenta for nutrient transfer

Question 8

evolution of placenta

Answer 8

extraembryonic membranes in fish, birds, and mammals, yolk sac dates back to aquatic ancestors; amnion, chorion, and allantois are innovations of amniotic egg which have been adapted to support embryonic development inside uterus

Question 9

marsupial evolution

Answer 9

only live in Australia and Americas, split and diverged following split of Pangea, could look similar to eutherians due to convergent evolution

Question 10

marsupial birth and nutritional dependence

Answer 10

baby is born, crawls back into pouch and sucks milk from mom, only comes out months later

Question 11

eutherians

Answer 11

complex placenta, longer pregnancies, young eutherians complete embryonic development within a uterus, joined to the mother by the placenta

Question 12

eutherian diversity

Answer 12

larger morphospace, more diverse, possible as increase in placentals could cause more advantageous life history traits or increased ecological opportunity

Question 13

primates

Answer 13

arose as adaptations to living trees, big toes and relatively moveable thumbs to grasp branches, fully opposable thumbs that can touch the ventral surface of all four fingers improved dexterity, enhanced depth perception and eye-hand coordination

Question 14

living primate 3 main groups

Answer 14

lemurs, tarsiers, anthropoids

Question 15

monkey evolution and divergence

Answer 15

arose in old world, new world monkeys 25 million years ago, experienced separate adaptive radiations over millions of years of separation

Question 16

ape evolution and diversity

Answer 16

apes evolved from old world monkeys 25-30 million years ago, include four genera: pongo, gorrilla, pan, and homo

Question 17

derived characters of humans

Answer 17

upright posture and bipedal locomotion, larger brans capable off language, symbolic thought, and artistic expression, production and use of tools, reduced jawbones and jaw muscles, shorter digestive tract

Question 18

homo sapien evolution

Answer 18

arose 200,000 years ago, homonins are extinct but more closely related to humans, fossils of 25 species

Question 19

earliest homonins similarities

Answer 19

oldest is sahelanthropus, share derived traits with humans: reduced canine teeth, relatively flat faces, increasingly bipedal, placement of foramen magnum underneath skull

Question 20

earliest homonins differences

Answer 20

small brains, larger teeth, projected jaws, smaller in stature

Question 21

human evolution misconceptions

Answer 21

hominins are separate lineages from chimps and diverges from a common ancestor, evolution of apes and humans is incomplete; human evolution is like a ladder directly from an ape but there are many branches, homo sapiens as survivors

Question 22

australopiths

Answer 22

paraphyletic assemblage of hominins 4-2 million years ago; anamensis, africanus, afarensis

Question 23

A. anamensis

Answer 23

earliest known australopith

Question 24

A. africanus

Answer 24

walked fully erect, humanlike hands and teeth

Question 25

A. afarensis

Answer 25

bipedal, small brain and body, long lower jaw

Question 26

“robust” autsralopiths

Answer 26

paranthropus boisei; sturdy skulls and powerful jaws

Question 27

“gracile” australopiths

Answer 27

afarensis and africanus; lighter feeding structures for softer foods

Question 28

dispersal of australopiths

Answer 28

southward africa: afarensis -> africanus -> sediba ; eastern africa: afarensis -> platyops, garhi, paranthropus, early homo

Question 29

early homo

Answer 29

homo habilis; handy man as utilized environment for tools, shorter jaws and larger brains than australopiths

Question 30

homo ergaster

Answer 30

fully bipedal, large-brained hominins; long slender legs with hip joints well adapted for long-distance walking; smaller teeth for softer foods

Question 31

homo erectus

Answer 31

first hominin to migrate out of Africa (due to walking!), migrated as far as Indonesia, extinct 200,000-70,000 years ago

Question 32

homo neanderthalensis

Answer 32

coevolution with sapiens did not descend directly; in europe and east from 350,000 to 40,000/28,000 years ago; thick-boned, large brain, buried dead, made tools, shorter bodies, stocky, large noses, culture*; closer to denisovans

Question 33

homo sapiens evolution

Answer 33

originated in africa. rapid expansion due to advances in cognition of humans; first group to show symbolic and sophisticated thought; culture and modification of the environment