Mammals Flashcards
general characteristics of mammals
body covered with hair great variety of integumentary glands endothermic dioecious highly developed olfactory sense highly developed brains most are vivparous placental
where are amniotes most adapted to staying
on land
aquatic mammals
may depend fully on aquatic conditions
their ancestors where terrestrial
they still have the general characteristics of mammals
breathe aur
their skeletons are similar to mammals than fish
3 mammals groups
Monotremes: egg-laying mammals e,g plata[cij
marsupials: pouched mammals
placentral mammals:
roles of the integumentary system
Protection.
comprises: Skin, appendages, hair, scales. feathers, nails, horns antlers
what is the only know mammal with keratin scales
pangolin
you can tell its a mammal because it has a hairy ventral side
diverse uses of hair
all animals with hair are mammals concealment behavioral signaling water proofing buoyancy thermal insulation
cetaceans
entirely aquatic mammals
e.g whales, dolphins and porpoises
sensory bristles are on their snouts(lost before o shortly after birth)
two kinds of hair in mammals
underhair: soft and dense (insulation)
guard hair: longer and coarse(protection)
in aquatic mammals underhair is dense and does not get wet
guard hair gets wet
what is hair made out of
dead epidermal cells containing keratin ( fibrous structural protein
shedding in mammals
hair is shed and regrown through out growth
2 annual molts: spring and fall
examples of modified hair
porcupine quills
whiskers on snouts: specialised for tactile sensing
horns
have 2 parts: interior bone sheath or keratin they are not shed not branched ( used for interaction)
Family Bovidae
family of mammals with horns
Antlers
made of solid bone and not keratin
shed (grown in the spring and shed after breeding season
branched
used for social interaction
Family cervidae
have antlers, mostly males
Caribou are an exception
4 classes of glands
sweat
scent
sebaceous
mammary
gland
an organ or group of cells that secrets a substance that is used or exctreted by the body
Sweat
occur over much of the body surface
types of sweat glands
eocrine glands: secrete a watery fluid which evaporated on the skin and cause cooling
these occur in hairless regions in most mammals
Apocrine glands: milky fluid that dries on skin an forms film
opens into hai folicles
Scent glands
used for communication marking territory, warning and defense
Most mustelids have the scent glands that open by duct to the anus
sebaceous glands
usually associated with hair follicles
secrete a greasy mixtture called sebum into hair follicles
cover the entire body of most mammals
in humans foun on the scalp and face
mammay glands
Produce milk
occur on all female mammals
secreted via nipples
monotremes lack nipples and the milk is secreted on the fur of the mothers belly
what group of mammals lack nipple
monotremes and milk is secreted on fur of belly