Mammals

hair

characteristic shared by all mammals

protection, concealment, waterproofing, sensory, insulation

functions of hair

middle ear bones

used to transmit sound in mammals

mammary glands

used to nourish young

diaphragm

allows efficient ventilation of lungs

specialized teeth and jaws

hep mammals feed on varieties of foods

heterodont

different specialized teeth in the tooth row (not all the same teeth)

polydont

seen in animals with sharks that have rows of teeth that replace each other

amniotes

what group did mammals evolve from?

therapsids

\-the only synapsid group to survive beyond the Paleozoic

\-developed errect gait

synapsids

have a pair of temporal openings in the skull for the attachment of jaw muscles

secondary bony palate

which permits breathing while holding prey/chewing food

allows young to breath while sucking milk

why is the secondary bony palate important mammals

cynodonts

where did high metabolic rates, enhanced jaw musculature, and the secondary bony palate develop?

diphyodont

teeth that are replaced only once as deciduous and permanent teeth while ancestral amniotes had continuous teeth replacement called polyphyodonts

stapes

homologous to the hyomandibula of other vertebrates that \n functioned for hearing in early synapsids

malleus and incus

developed from articular and quadrate bones that previously served as jaw joint but became reduced in size to better transmit sound vibrations

monotremes and therians

2 clades of living mammals

marsupials and placental mammals

what does the therian group consist of

thicker

mammal skin is generally ______ and serves as interface between animal and its environment

epidermis, dermis

Hair follicle is an ______ structure,but lies deep in ________ of skin

sebaceous glands

glands associated with hair follicles

underhair

serves as insulation by trapping a layer of air underneath it

molting

seasonal shedding of hair

horns

hollow sheaths of keratinized epidermis that surround a core of bone rising from skull

antlers

branched structures made solid bone that occur in the deer family.

sweat glands

tubular, highly coiled glands found over much of the body surface of mammals

scent glands

Allow for communication with members of the same species by marking territory, warning, and defense signals.

oils to lubricate skin and hair

what do sebaceous glands secrete?

homodont

uniform tooth patterns seen in reptiles

incisors

teeth with simple crowns with sharp edges for snipping or biting

canines

teeth with long conical crowns used for piercing

premolars

teeth with compressed crowns with one or two cusps for shearing and slicing

molars

larger bodies and variable cusps for crushing and grinding

3 incisors, 1 canine, 4 premolars, and 3 molars

primitive mammal tooth formula

deciduous

how are most mammal teeth (except molars) classified

insectivores

\-shrews,moles, anteaters, and most batsare usually small.

\-Eat insects and other small invertebrates

short intestinal tract and pointed teeth

adaptations of insectivores

herbivores

feed on grasses and other vegetation

large and four chamberes

ruminant stomach

food swallowed and then re-chewed before nutrients are absorbed

how does digestion occur in ruminants?

cecum absent or reduced

adaptions of carnivores

omnivores

feed on both plants and animals

bats

only mammals that can fly

echolocation

how do bats sense their environment

no

are bats blind

scent

how do plants attract bats to pollinate them

primates

have grasping fingers, flat fingernails, and forward-pointing eyes with binocular vision and depth perception

simians

primate group consisting of monkeys and apes

new world monkeys have a grasping tail

difference between new and old world monkeys

larger cerebrum, no tail

how do apes differ from monkeys

hominids

human fossil grouping that includes apes

hominins

all hominid fossils placed closer to humans than to chimpanzees (humans are the only extant species)

less robust with smaller canines

differences in human jaw

foramen magnum

the hole in which the spine passes to the skull

has shifted more ventrally to allow bipedal locomocation

significance of foramen magnum in human evolution

shorter pelvic bones and s shaped vertebral column

more adaptations that support human bipedalism