EARTH HISTORY UNIT VOCABULARY TERMS

1. Absolute Dating - Any method of measuring the age of an event or object in years. The actual age for a rock or mineral.
2. Adaptation - A trait that increases the chances that an organism will survive and reproduce.
3. Artificial selection - The breeding of plants and animals with desired traits to attempt to produce off spring with these same traits.
4. Biological evolution - The change over time of living organisms.
5. Cenozoic Era -Era that began about 66 million years ago, known as the “Age of Mammals”.
6. Continental drift theory - Theory that states that the gradual shifting of Earth’s plates causes continents to change their global positions over time.
7. Convergent plate boundary - The boundary formed by the collision of two plates.
8. Correlation - The matching up of rock layers from different locations.
9. Darwin - He was a naturalist who proposed and provided scientific evidence that all species of life have evolved over time from common ancestors through the process he called natural selection.
10. Daughter Isotope - The stable isotope that results from radioactive decay.
11. Divergent plate boundary - The boundary between two tectonic plates that are moving away from each other.
12. Eon - The largest division of geologic time.
13. Epoch - A subdivision of a geologic period.
14. Era - A unit of geologic time that includes two or more periods
15. Evolution - The change in population of a species over time.
16. Extinction Rate -The rate at which species die off.
17. Extinction - The evolutionary termination of a species caused by the failure to reproduce and the death of all remaining members of the species; the natural failure to adapt to environmental change.
18. Fossil record - The complete body of fossils that shows how species and ecosystems change over time.
19. Fossil - Evidence of past life preserved in rock.
20. Fossilized - The process of becoming a fossil.
21. Geologic Time scale - The standard method used to divide the Earth’s long natural history into manageable parts.
22. Half-life - The time needed for half of a sample of radioactive substance to undergo radioactive decay.
23. Index fossil - A fossil found in a narrow time range but widely distributed around the earth; used to date rock layers
24. Isotope - An atom that has the same number of protons(or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (thus a different atomic mass).
25. Law of superposition - States that the oldest rocks lie on the bottom and the youngest rocks are on top of any undisturbed sequence of sedimentary rocks.
26. Mesosauras - An example of a species that helped support the continental drift hypothesis.
26. Mass extinction - Occurs when a large proportion of the earth’s species go extinct in a relatively short period of time.
27. Mesozoic era - Era that began 245 million years ago, known as the age of the dinosaurs.
28. Mutation - A random change to a gene that results in a new trait.
29. Natural selection - survival of the