Across
- 4. live young
- 5. insulating feathers
- 8. class of lancelets
- 9. finned type of fish with spiny fins
- 11. egg feature for gas exchange
- 12. class of tunicates
- 13. flying feathers
- 17. scratching birds
- 19. eggs are in the mother, but nourished by yolk
- 21. type of circulatory system in vertebrates
- 22. finned type of fish that may have given rise to amphibians
- 24. chambers in an amphibian heart
- 27. perching birds
- 30. (2 words) egg feature for nutrients
- 34. type of fertilization in fish
- 35. number of classes of vertebrates
- 37. bladder lacking in sharks so they have to swim or sink
- 38. changes in an amphibian during development
- 39. modified sweat glands for feeding young
- 40. order of reptiles with alligators
- 43. order of reptiles with snakes
- 45. means 4 legs
- 46. suborder of primates that means human like
- 49. egg feature for wastes
- 50. skeleton on the inside
- 51. (2 words) allow constant oxygen for birds
Down
- 1. cartilaginous fish
- 2. can be used to determine what mammals eat
- 3. eggs are laid and hatch externally
- 6. egg laying mammals
- 7. predator birds
- 8. amphibians with tails
- 10. order with frogs and toads
- 14. flap that pushes water over the gills
- 15. web footed birds
- 16. chambers in a bird heart
- 18. jawless fish
- 20. type of mammals developing completely in the uterus
- 23. legless amphibians
- 25. generate heat with metabolism
- 26. get heat from the environment
- 28. has 2 chambers in fish
- 29. used with lungs to get oxygen in amphibians
- 31. order of reptiles with turtles
- 32. subphylum of animals with backbones
- 33. long flexible rod that can become a spine
- 36. order of mammals with opposable thumbs
- 41. bony fish
- 42. egg feature for protection
- 44. mammals with pouches
- 47. water proofing feathers
- 48. line system for detecting vibration in fish