Across
- 4. An explanation based on evidence confirmed many times through observation
- 6. Structures that are similar in different species and have different functions
- 9. Traits passed down from one generation to the next
- 11. Change in species over a long period of time
- 13. A group of related organisms that can breed and produce fertile offspring
- 15. Dating of rocks based on carbon or potassium-argon
- 16. When species have to fight for resources to survive
- 18. An earlier relative shared with another species
- 19. Where nature selects which organisms survive to reproduce
Down
- 1. Remains of dead organisms that have been preserved
- 2. A tree diagram that shows evolutionary relationships among different species
- 3. Molecules made up of long chains of amino acids
- 5. Characteristics that make an organism well suited to a particular envrionment
- 7. Differences in gene traits from the blending of DNA from mother and father
- 8. Parts of the body that serve no purpose but may have in the past
- 10. Genetic molecule that codes instructions for our bodies
- 12. Where people select which characteristics to breed
- 14. Early stages of development where different species look similar
- 17. A species that no longer exists on Earth