Mammals

Question 1

what skull type did mammals evolve from

Answer 1

synapsids

Question 2

where are the openings in the skulls of synapsids

Answer 2

in the roof

Question 3

when did synapsids start to diversify

Answer 3

in the permian

Question 4

put these in order of their evolution:
cycodonts
pelycosaurs
mammals
therapsids

Answer 4

pelycosaurs
therapsids (in permian)
cynodonts
mammals

Question 5

the small ectothermic, hairless ancestors to mammals evolved into the …

Answer 5

endothermic, furry ,mammals

Question 6

why are cynodont thought to be a step in mammalian evolution

Answer 6

had mammal like feature in skull like teeth
its the reptile mammal connection
it laid eggs
had a secondary palate

Question 7

what is diphyodonts

Answer 7

teeth replaced only once from milk teeth to permanent teeth

Question 8

how have mammal skulls and teeth evolved

Answer 8

diphyodonts
bony secondary palate
single lower jaw bone

Question 9

mammal evolution came from what type of lineage

Answer 9

therapsids

Question 10

therapsids are the only synapsid group to survive past the…

Answer 10

paleozoic

Question 11

the cyncodonts were the last therapsid group to evolve and surrived into the mesozoic… why is it considered a mammal reptile connection

Answer 11

laid eggs
more mammal like skull
secondary palate

Question 12

what did the early mammals in the triassic look like

Answer 12

small, mouse sized mammals

diphyodonts

Question 13

explain the cenozoic radiation of mammals

Answer 13

after the K-T extinction, new habitats vacated

many amniote groups vacated at end of cretaceous
mammals came in and survived

Question 14

feathers define birds but what defines mammals

Answer 14

hair

Question 15

how is the skin in mammals different than other animals

Answer 15

thicker

hair

Question 16

how does the hair grow

Answer 16

continuously by rapid proliferation of cell in folicle

hair in shaft shift up
accumulate keratin, then dies

Question 17

sheep and cattle have true horns… what are these sturcture wise

Answer 17

hollow sheath of keratinized episdermis
surround core of bone from skull

continuously grow

Question 18

antlers are composed of…

Answer 18

solid bone once mature

seen in deer, mouse

Question 19

integumentary glands come from the skin. list the type of glands and what they do:

Answer 19

eccrine sweat glands - cools skin

appocrine sweat glands 0 milky fluid, oily, smelly pheromone, territorial marker, warning, adrenaline

sebaceous glands - scent gland, hair follicles, greasy hair

mammary glands - modified appocrine glands
make milk in females

Question 20

are all mammals viviparous

Answer 20

no because monotremes lay eggs

Question 21

all three groups of mammals (monotremes, marsupials, placentals) are derived from…

Answer 21

cyncodont

Question 22

when did the first mammals appear

Answer 22

in the jurassic

Question 23

the sinodephys was the earliest known…

Answer 23

marsupial

Question 24

when did the diversification of placental orders happen

Answer 24

in the cretaceous

Question 25

the prototherian lineage refers to the …

Answer 25

monotremes, oviparous

Question 26

do monotremes have nipples

Answer 26

nope no nippies here

they have pores that milk comes out of, sweat milk

Question 27

marsupials come from what lineageq

Answer 27

therian lineage

Question 28

what distinguishes a marsupial

Answer 28

pouch

Question 29

are marsupials oviparous, viviparous or ovoviviparous

Answer 29

viviparous, live young

but lack a complete placenta

Question 30

to marsupials have nipples

Answer 30

yes, multiple

Question 31

what are some characteristics of placentals

Answer 31

lost epipubic bones - can only allow small offsrping to pass through

wider pelvic bone
placenta

Question 32

what are the components of the eutherian placenta

Answer 32

yolk sac, allantois + chorion = placenta, amnion

Question 33

limbs are made for walking. distinguish between plantigrade, digitigrade, ungiligrade

Answer 33

plantigrade - walking feet flat on ground (primate, rodents, carnivores)

digitigrade - walk on toes, cats and dogs

ungulirade
- walk on nails
horse, deer, antelope

Question 34

the return to the ocean was a separate event… name the 3 orders we talked about in class

Answer 34

orer carnivore (wlaruses, seals, sea lions)

order cetacean (whales, dolphins)

order sirenia (manatees)