Geo History/Change Over Time

2. The scale of time used by scientists in terms of geological events.
9. An extinct fossil that used to live in a geologic period.
11. A law that states that any rock layer below another must be older than the layer above it, and that intrusions are always younger than the layer that they intruded on.
12. The phenomenon where organisms best suited to their environment can reproduce more, and become a dominant part of the species.
13. The process using half-lives to calculate the age of any fossil by comparing the amount of decayed to non-decayed material.
14. The time it takes for there to be a 50% chance that any atom decays.
15. The fact that Earth's geological events have not changed much. Ex: Volcanoes have always existed and formed the same way
16. Variations of an atom in which the number of neutrons is different.

1. The preserved parts of past organisms.
3. A "layer" of rock that forms when rising magma cools into igneous rock in the middle of other rock layers.
4. A trait that an organism inherits or acquires that helps it survive.
5. The chronological ordering of all fossils into one timeline that shows the history of all life.
6. The age of a fossil or object relative to another fossil or object.
7. The amount of differences in genetic material of animals in the same species.
8. The exact(almost) age of a fossil or object.
10. An event that changes the ability of a certain organism to survive, only the best adapted organisms can survive.