Across
- 4. humanlike primates
- 5. traits that do not appear in the fossils of common ancestors
- 7. tree-dwelling
- 9. structures that can be used for the same purpose and can be similar in construction but aren't related
- 10. traits that do appear in ancestral forms
- 12. a tail which functions as a fifth limb
- 14. also known as selective breeding
- 15. active at night
- 17. reduced forms of functional structures
- 18. measure of a trait's relative contribution to the next generation
- 19. a thumb or toe set apart from the other digits
- 20. adaptations that allow organisms to blend into their surroundings
- 21. anatomically similar structures inherited from a common ancestor
Down
- 1. an organism's early prebirth stage of development
- 2. active during the day
- 3. adaptations that allow species to resemble other species
- 6. changes in groups of organisms over time
- 8. large-brained, diurnal monkeys and hominoids
- 11. overlapping fields of vision
- 13. the study of the distribution of plants and animals on Earth
- 16. selection theory of evolution developed by Darwin