| A | B |
|---|
| what do some scientists think birds should be classified as? | reptiles |
| what did birds probably evolve from? | the thecodont reptiles |
| birdlike vertebrate found | protavis |
| earliest fossil known to have feathers | Archaeopteryx |
| aves | diverse class of vertebrates that birds make up |
| how many diff species of birds are alive today? | at least 9000 |
| which birds account for 60% of avians? | perching songbirds |
| what are feathers made of? | keratin |
| what purposes to feathers have? | insulation, protection against weather, form smooth, low-friction flying surface |
| contour feathers | make up most feathers on birds body, form smooth flying surface. have stiff centra shafts w/ side branches |
| barbs | side branches of centrral shaft of wing |
| barbules | tiny hooked branches of barbs |
| dwon feathres | cover young birds and are clustered @ base of contour feathers in adults. have short shafts w/ tuft of long, fluffy barbs @ end |
| what does the strength of bird bones come from? | calcium |
| how is a birds skull modified to reduce weight? | large eyes in comparison to head, jaw becomes tooth-less beak |
| fused bones | lost bones - the bones of the avian skeleton |
| furcula | wishbone in poultry |
| wing traits | thick in front, tapering toward back |
| muscular system makes up how much birds body weight? | more than 1/2 |
| do birds have skin glands? | no, except for oil gland @ base of tail |
| are birds endothermic or exothermic? | endothermic |
| energy | birds generate it with their wings and conserve it with their feathers |
| how do birds obtain large amounts of oxygen? | they have air sacs that entend throughout their bodies |
| crop | a storage area of the digestive tract where food is softened |
| gizzard | a digestive organ with muscular walls that often contains small stones swallowed by the bird. grounds food digested to a pulp |
| villi | fingerlike projections of the intestinal wall that increase the surface area across which nutrients are absorbed |
| how many ovaries do females have? | just one |
| where does internal fertilization occur? | inside the cloaca, then made into an egg, then leaves through the cloaca |
| chalaza | a ropelike strand of tissue connected to the chorion that supports the albumin (egg white) |
| courtship behaviors | songs are matin calls, males establish territories, males spread brightly colored feathers and parade around, some build elaborate nests and decorate, some offer fish or water weed |
| monogamy | when animals have only one mate with whom they remain throughout the breeding season. some, like eagles, for life |
| circadian rhythm | a sequence of behaviors that occur regularly at about 24-hour intervals |
| Ways of getting food | Seed-eating, nectar sipping, ripping and tearing, swimming, climbing, probing, fish-catching |
| What body part is manily used for getting food? | the beak - it is adapted for certain purposes with each specie |
