Across
- 1. isolation. Physical differences prevent species from mating.
- 3. structure. Similar body parts in different species that evolved for the same purpose, but don't share a common ancestry.
- 8. Species change over time through genetic differences and natural selection.
- 9. of the fittest. The best-adapted organisms are more likely to survive and reproduce.
- 11. isolation. Species separated by physical barriers may evolve into new species.
- 12. divergence. Populations accumulate genetic differences over time.
- 14. Preserved remains or traces of ancient organisms.
- 15. isolation. Species living in different habitats don't reproduce together.
- 17. drift. Random changes in traits can occur, especially in small populations.
- 18. selection. Organisms with helpful traits survive and reproduce more.
- 19. isolation. Different mating behaviors prevent species from interbreeding.
- 20. Changes in DNA can lead to new traits.
- 21. Traits are passed down through DNA.
Down
- 2. selection. Humans choose specific traits in plants and animals.
- 4. The process by which new species form.
- 5. When a species completely disappears because it can't adapt.
- 6. isolation. Species that reproduce at different times can't mate.
- 7. structure. Similar body parts in different species due to common ancestry.
- 10. structure. Body parts that no longer serve their original function.
- 13. How well an organism survives and reproduces in its environment.
- 16. A helpful trait that improves survival and reproduction.