Across
- 3. Comparing structures of two different species.
- 4. A layer of sedimentary rock.
- 6. A branch of medicine concerned with the study of embryos and their development.
- 8. Layers of sediment which are compressed and glued together by chemical reactions and pressure.
- 10. The time it takes for half the radioactive atoms in the substance to decay.
- 11. A result of natural selection. The characteristics that are selected for, are determined by the specific selective pressures of the environment.
- 14. The process of forming a fossil from a living organism.
- 15. When one ancestral species evolves into one or more new species.
Down
- 1. A diagram that shows the evolutionary history if a species or a group of species.
- 2. Related organisms that share common characteristics and are capable of interbreeding.
- 3. A diagram that shows all the members of a clade, including the common ancestor.
- 5. A subdivision of the geological time scale.
- 7. The preserved impressions of an organism.
- 9. The change in heritable characters of a population or species over time.
- 12. Estimating the age of rocks or fossils in (millions of) years.
- 13. The study of where in the world plants and animals live.