| A | B |
|---|
| external fertilization | type of fertilization of fish and frog eggs whereby the female deposits unfertilized eggs in water and the male fertilizes them |
| internal fertilization | type of fertilization in reptiles, birds and mammals where the male sperm enters the female's body and fertilizes the eggs there |
| scales | type of skin covering in reptiles that can range from tiny, interlocked pieces to huge plate-like coverings |
| molt | when a reptile outgrows its skin it must ___. |
| snakes | legless reptiles with no sense of hearing and poor sight, but with keen sensitivity to nearby body heat |
| lizards | small crawling reptiles with 4 legs and a tail ; they have organs of hearing but no heat sensors |
| leathery shells | reptile eggs are able to be laid on land rather than in water because of this |
| tortoise | land-dwelling reptile with flat feet and large digging claws |
| turtle | water-dwelling reptile with webbed feet and a streamlined shell |
| crocodile | huge, crawling reptile with a narrow snout and teeth that show when the mouth is closed |
| alligator | huge, crawling reptile with a broad snout and many teeth which are hidden when the mouth is closed |
| cold blooded | because reptiles take on whatever temperature their environment is, they are said to be __. |
| warm blooded | Because birds and mammals generate heat energy to keep their bodies at a constant temperature, they are said to be __. |
| contour feathers | large, stiff feathers that are used for flight |
| down feathers | short, fuzzy feathers used for insulation |
| air sacs | birds that fly have these internal structures to supply needed additional oxygen that flying requires |
| talons | large, razor-sharp claws of birds of prey |
| territory | area of land that a bird will claim for itself and its mate |
| migrate | To avoid cold temperatures and continue to have good food supplies all year, many birds will ____. |
| sun and stars | During migration, some birds use these heavenly bodies to keep flying in the right direction |
| mountain ranges & coastlines | During migration, some birds use these natural features on earth to keep flying in the right direction |
| magnetic centers | During migration some birds use these special structures in their brains to keep them flying in the right direction |
| mammary glands | glandular structures that produce milk for the young of all mammals |
| monotremes | an unusual order of mammals that actually lay eggs (example: playtpus) |
| marsupials | an order of mammals that carry their young in a pouch until they are more developed (examples:kangaroo, koala, wallaby) |
