| A | B |
|---|
| mammal | an endothermic vertebrate that has hair and mammary glands |
| what class to mammals belong to? | Mammalia |
| how many living species of mammals are there? | about 4500 |
| what are the biggest and smallest mammals? | smallest - pygmy shrew, biggest - blue whale |
| what did mammals probably evolve from? | therapsids |
| advantages of being endothermic | could search for food at night when exothermic animals couldn't, avoiding predator dinasaurs |
| disadvantages of beign endothermic | required about ten times more food than ectothermic reptiles did, which limited population b/c of food demand |
| what triggered the rapid evolution of mammals? | denosaurs died out, leaving many environmental niches available, and food and space were no longer in competition |
| what percent of a mammals food is used to generate body heat? | about 90% |
| how are the three groups of mammals classified? | by the way they reproduce |
| Monotremes | mammals that lay eggs and have a cloaca into which the urinary, digestive, and reproductive tracts open |
| which were the first mammals to evolve from therapsids? | monotremes |
| can monotremes control their body temperature? | yes, but not as well as other mammals can |
| what are the three species of monotremes? | duck-billed platypus and the two species of echindas |
| echindas | monotremes, spiny anteaters, covered w. coat of thick hair and spines |
| marsupials | mammals that give birth to small, underdeveloped young that develop in the mother's external pouch |
| how many species of marsupials are there, and where do most of them live? | 250, Australia or nearby islands |
| opossum | marsupial, lives in N and S America |
| placental mammals | mammals whose young develop inside the mother's body and are nourished by the mother's body until birth |
| what percent of mammals are placental? | almost 95% |
| what order do rodents belong to? | rodentia |
| how many species are included in rodentia? | more than 1700 |
| rodents | herbivorus, have 5 clawed toes on each limb, and a pair of very sharp teeth that grow throughout life |
| what order do bats belong to? | Chiroptera |
| how many species belong to the order Chiroptera? | 925 |
| bats | live wherever there are trees, can fly, wide varieties of teeth, reflecting what they eat |
| lagomorphs belong to what category? | lagomorpha |
| how many species belong to the order lagomorpha? | about 65 |
| lagomorphs | rabbits, hares, pikas. differ from rodents in teeth structure |
| what order do carnivores belong to? | carnivora |
| how many species belong to the order carnivora? | 240 |
| carnivores | mostly strictly-meat eating but some exceptions. have pair of long, sharp teeth, strong haws, clawed toes |
| pinnapeds | carnivores adapted to an aquatic lifestyle |
| Cetaceans belong to what order? | cetacea |
| Cetaceans | torpedo-shaped bodies w/ long, pointed head and no neck. broad, flat tial. completely aquatic |
| Sirenians belong to what order? | sirenia |
| Sirenians | aquatic mammals that have large, slow-moving, barrel-shaped bodies |
| ungulates belong to what orders? | Artiodactyla and Perissodactyla |
| Artiodactyla | hoofed mammals with an even number of toes |
| Perissodactyla | hoofed mammals with an odd number or toes |
| Insectivores belong to which order? | Insectivora |
| Insectivores | insect-eating mammals with high metabolic rate and sharp claws for diggin |
| Elephants belong to what category? | Proboscidia |
| Elephants | massive bodies, large heads, flat ears, short neck, thick skin with little hair, tusks that dig |
| Primates belong to which order? | Primates |
| How many species belong to the order Primates? | 175 |
| Primates | have hands with opposable thumbs, large eyes that face forward |
| most mammalian skeletal structures enable the animal to....... | run fast |
| What is one of the most important adaptions for different types of animals and they way they eat? | Specialized teeth |
| incisors | conelike teeth in the front of the mouth, specialized for stripping and cutting |
| canines | long, pointed teeth on the sides for piercing and tearing |
| molars and premolars | broad, flattened teeth in the back of the mouth for crushing and tearing |
| besides teeth, what else reflects a mammals diet and how? | the length and structure of a mammal's digestive tract. mammals only eating plants have longer dig. tracts than mammals that only eat meat b/c plants have tough fibers that are hard to break down |
| rumen | a stomch chamber containing bacteria that digests the cellulose in plant tissues |
| cud | the partially digested plant material in the rumen |
| cecum | a pouch located at the end of the small intestine that contains bacteria that digest plant material and enable the mammal to absorb the nutrients |
| diaphram | a dome-shaped sheet of muscle separating the chest cavity and the abdomen |
| air sacs | are millions of them located at the ends of breathing passages in mammalian lungs in which the exchange of gasses occurs |
| mammal circulation | double-loop circulatory system with a four-chambered heart |
| kidneys | organs that remove cellular wastes and regulate the water balance in the body |
| medulla | the inner part of each kidney |
| cortex | where urine formation begins |
| fertilization for mammals | ALL internal |
| reproduction in monotremes | lay eggs, but need to be kept warm. |
| reproduction in marsupials | give birth to small, underdeveloped young. attached to nipple in pouch and gets nutrients from there. |
| reproduction in placental mammals | the embryo remains inside the mother and develops more fully than marsupial young |
| placenta | an organ through which nutrients, oxygen, CO2, and wastes are exchanged between the mother and the embryo |
| gestation period | the time that the embryo stays inside the mother's body |
