The Vertebrates

1. Gill slits, a tail, and a notochord are found in all vertebrates, but in humans only in the _______ stage.
9. Birds can generate their own body heat and do not depend on environmental temperatures because they are __________.
10. Amphibians have a ______-chambered heart.
11. Unlike in amphibians, fertilization of the egg by sperm in reptiles is __________.
13. These vertebrates keep the tail and gills slits into adulthood
14. Amphibian means "two _______".
15. A honeycomb design of hollow bones and feathers allow for this major adaptation of birds.
17. The class of vertebrates most closely related to dinosaurs.
18. A popular reptile that has changed very little since they evolved.
22. egg Reptiles can live in dry regions due to the adaptation of the shelled, _________ ____.
25. Vertebrates arose from invertebrates but share the Phylum __________.
26. A unique adaptation of cartilagenous fishes over the jawless fishes giving sharks lift in the water.
27. Birds and mammals have a _________-chambered heart.
29. A diverse adaptation that differs among birds allowing them to find food and inhabit a variety of environments are their ________.
31. A jawless fish that acts as parasites to other fish in fresh and salt water.

2. An example of this special type of mammal is the duck-billed platypus that lays eggs rather than live young.
3. A covering over the gill slits is an evolutionary advantage of bony fishes over cartilagenous fishes.
4. The skin and eggs of amphibians requires them to live in or near _________.
5. A special nervous system adaptation used by sharks and rays to sense water pressure changes caused by approaching predators and prey.
6. Structures that define mammals as a unique group of vertebrates.
7. A group of mammals such as kangaroos and koalas whose young are born early and finish development in a pouch.
8. Class Chrondrichthyes includes the fishes whose skeleton is made of ________.
12. An adaptation of mammals with great diversity in structure and function.
16. The most primitive living vertebrates are the _______ ______.
19. The genus and species name of human beings with the most advanced cerebral cortex for thinking and feeling.
20. Bony and cartilagenous fishes have a _____-chambered heart.
21. Salamanders and frogs are in the Class ______.
23. All amphibians lose their gills as they change from larvae to adult during __________.
24. A unique covering seen only in mammals.
28. Vertebrates are animals with a vertebral column or ____________.
30. This specialized structure in bony fishes allow them to sit motionless at different depths of water, unlike cartilagenous fishes which must constantly move their fins.