Across
- 3. a structure no longer needed by an organism
- 5. comparing similarities in embryonic development
- 8. remains of living organisms
- 10. when a big population goes to a very small one
- 11. to make a new species
- 12. a structure that several species share but have different functions
Down
- 1. the distribution of organisms
- 2. differences, variety, many different forms
- 4. a structure that has the same function, but different structure
- 5. change over time
- 6. trait that increases the ability to survive
- 7. ability to reproduce fertile offspring
- 9. genes available for intermixing in a population