| A | B |
|---|
| incubate | to keep eggs warm until they hatch |
| contour feathers | strong, lightweight, give color, help fly |
| down feathers | soft and fluffy, give insulation |
| preening | process of using beak to rub oil on feathers |
| mammary glands | glands that produce milk for feeding young |
| herbivores | animals that eat only plants |
| carnivores | animals that eat only other animals |
| omnivores | animals that eat both plants and other animals |
| placentals | mammals in which embryos develop inside the uterus |
| gestation period | amount of time an embryo develops in the uterus |
| placenta | saclike organ inside the uterus that absorbs food and oxygen from the mother's blood |
| umbilical cord | attaches the embryo to the placenta |
| marsupial | pouched mammals that give birth to immature young |
| monotreme | mammals that lay eggs with tough, leathery shells |
| mammal | endothermic vertebrate that has hair and produces milk to feed its young |
| kangaroo | example of a marsupial |
| platypus | example of a monotreme |
| cow | example of a placental |
| opossum | example of a marsupial that lives in North America |
| porpoise | example of a placental |
| endotherm | animals that keep a constant body temperature |
| incubation period | amount of time an embryo develops in the egg |
| herbivore | animals that eat only plants |
| shaft | stiff central part of a contour feather |
| barb | side branches of a contour feather |
| crop | first portion of the digestive system of birds |
| gizzard | often contains small stones to help grind up food |
| keel | large breastbone of birds |
| lift | the upward force on wings that keeps a bird in the air |
| Bernoulli effect | curved shape of the bird's wing forces the air on top to move faster than the air underneath creating low pressure in the air |
| brooding | when a bird sits on its egg until it hatches |
| precocial | birds that hatch fully active |
| altricial | birds that hatch weak, naked, and helpless |
| flightless birds | ostrich, kiwi, penguin |
| birds of prey | eagle, hawk, falcon |
| water birds | wood duck, common loon, blue-footed booby |
| perching birds | wrens, robins, sparrows, parrots, chickadees |
| diaphragm | large muscle that helps bring air into the lungs |
| blubber | layer of fat that keeps some mammals warm |
| incisors | teeth in the front of the mouth used for cutting |
| canines | stabbing teeth used for grabbing food and holding on |
| molars | flat teeth used for grinding |
| milk teeth | a mammal's first small teeth |
| toothless mammals | anteaters, armadillos, aardvarks, sloths |
| insect eaters | moles, shrews, hedgehogs |
| rodents | squirrels, mice, rats, guinnae pigs, porcupines, chinchillas |
| lagomorphs | rabbits, hares, pikas |
| flying mammals | bats |
| carnivores | coyotes, raccoons, cats, walruses |
| hoofed mammals | horses, pigs, deer, rhinoceroses |
| trunk-nosed mammals | elephants |
| cetaceans | whales, dolphins, porpoises |
| sirenia | manatees |
| primates | monkeys, apes, humans |
