mammals

which class are mammals in?

mammalia

3 main groups of mammals

monotremes, placentals, marsupials

2 most significant characteristics unique to mammals

mammary glands, hair

what is the single lower jaw bone in mammals called? (where the teeth are attached)

dentary

how many middle ear bones do mammals have?

3

why did mammals originally need endothermy? (when they lived with dinosaurs)

to survive cold night temperatures

how many chambers do mammal hearts have?

4

the diaphragm allows ______ even when standing still

breathing

the complete secondary palate _____ nursing efficiency

increases

what is the diphyodont condition?

having 2 sets of teeth

explain heterodont dentition

different teeth for different functions

which type of skull do mammals have?

synapsid

_____ evolved from pelycosaurs and then therapsids/cynodonts

mammals

therapsids were the first animals to have…

upright limbs beneath body

basic “principle” of carrier’s constraint

some vertebrates cannot move and breathe at the same time

_______ were the group of therapsids who survived the mass extinction and diversified to become mammals

cynodonts

were mammals’ synapsid ancestors dinosaurs?

no

mammals’ synapsid ancestors showed an early trend towards thermoregulation due to the presence of…

whiskers

what does “cynodonta” mean?

dog teeth

the earliest mammals evolved what specific strategy to survive during the age of dinosaurs?

small size

since dinosaurs were active during the day, early mammals were likely…

nocturnal

what 2 “factors” caused mammals to evolve quickly?

short lifespan, frequent reproduction

placental mammals are part of infraclass…

eutheria

what does “eutheria” mean?

true true birth

what does “theria” mean?

true birth

what is the “defining characteristic” of the therians?

live birth

what is the “defining characteristic” of monotremes?

laying eggs

2 example monotremes

spiny anteater, platypus

what does “monotremata” mean?

one hole

what one hole are monotremes named after?

cloaca

2 places that monotremes live

australia, new guinea

where on their mothers do monotreme babies get milk from?

sweat patch

4 example marsupials

opossums, kangaroos, koalas, wombats

70% of marsupials also live in these 2 places

australia, new guinea

marsupial babies are born in the ______ stage

embryonic

another term for marsupial pouch

marsupium

in their own habitats, marsupials diversified to fill the same _____ as placentals

niches

common name for thylacine

tasmanian tiger

what group of mammals did thylacines fall into?

marsupials

the thylacines were killed off by… (2)

humans, other placental mammals

the most reproductive investment in marsupials is during…

lactation

the most reproductive investment in eutherians is during…

gestation

are placental mammals or marsupials typically more successful in surviving after birth?

placental mammals

humans develop _____ for their body size compared to other mammals

slowly

as mammals evolved, their ___ __ placenta got replaced by the ______ placenta

yolk sac, chorioallantoic

are eutherians the largest group of mammals?

yes

modified versions of these 4 bones are unique to placental mammals

ankle, wrist, jaw, pelvis

horns and antlers are only found in this group of mammals

eutherians

describe structure of true horn

hollow keratinized epidermis around bone core

are true horns usually shed?

no

are true horns ever branched?

no

do true horns grow continuously?

yes

are true horns present in both sexes?

yes

describe makeup of antlers at maturity

solid bone

what is the name of the vascularized skin covering antlers?

velvet

the growth patterns/schedule of _____ revolve around breeding season

antlers

are rhino horns true horns?

no

describe makeup of rhino horns

keratin filaments cemented together

what is the largest order of mammals?

rodentia

the ____ of rodents grow continuously

teeth

3 example organisms within order lagomorpha

rabbits, hares, pikas

lagomorphs have similar dentition to…

rodents

primates have __ digits with ____ fingernails

5, flat

within order primates, humans are in family ______

hominidae

what is the common name for family hominidae?

great apes

3 example organisms within superorder xenarthra

sloths, armadillos, anteaters

do anteaters have teeth?

no

sloths and armadillos have ___-like teeth

peg

example organisms within order chiroptera

bats

what unique ability (to mammals) does order chiroptera have?

flying

example organisms within order proboscidea

elephants

elephant ___ are actually upper incisors

tusks

2 example organisms within order sirenia

dugongs, manatees

example organisms within order hyracoidea

hyraces

organisms in order carnivora are all flesh-eating predators except for…

giant panda

what 3 organisms are pinnipeds?

seals, sea lions, walruses

2 example organisms within order soricomorpha

moles, shrews

2 key characteristics of soricomorphs

sharp spiky teeth, pointed snout

key characteristic of order perissodactyla

odd-toed

4 example organisms within order perissodactyla

horses, zebra, rhinos, tapir

what are ungulates?

hoofed mammals

perissodactyla have ______ stomachs

simple

key characteristic of order artiodactyla

even-toed

most artiodactyla have ______ stomachs

partitioned

3 example organisms within infraorder cetacea (within order artiodactyla!)

whales, dolphins, porpoises

6 example organisms within order artiodactyla

antelopes, hippos, swine, cattle, deer, camels