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