Deep Sea Vents

4. explosion The relatively rapid appearance, around 542 million years ago, of most major animal phyla, as demonstrated in the fossil record. This was accompanied by major diversification of other organisms.
7. The scientific study of prehistoric life.
8. sea vents A fissure in a planet's surface from which geothermally heated water issues.
9. of superposition A key axiom based on observations of natural history that is a foundational principle of sedimentary stratigraphy and so of other geology dependent natural sciences
10. tectonics A scientific theory that describes the large-scale motion of Earth's lithosphere.

1. A period of time marked by distinctive character, events, changes on earth, etc.
2. theory Several key organelles of eukaryotes originated as symbioses between separate single-celled organisms.
3. generation an obsolete body of thought on the ordinary formation of living organisms without descent from similar organisms.
5. dating The science of determining the relative order of past events, without necessarily determining their absolute age.
6. The amount of time required for a quantity to fall to half its value as measured at the beginning of the time period.