Fossils Flashcards
Original preservation ex.
Tar, freezing, amber, oxygen deprivation
Evolution
The change in population as a result of an altered environment
Index fossils
Tell how old the surrounding rocks are if one knows how old the fossil is
Best index fossil and when
Tribolit end of precambyran era
Qualities of a good index fossil
Widespread
Existed during short period of time
Were very abundant
Unique
Another name for petrified fossils
Permineralized fossils
What are petrified or permineralized fossils?
The hard parts have been removed and replaced by rock minerals
Whats Molds and casts?
A cast is when a mold fills with sediment
Trace fossil
Evidence of past life ex. Footprints
Coprolite is…
Dinosaur feces
Relative age
Compared to other things
Dendrochronology
Matching up tree rings
Varve
Layer of clay and silt
Radiometric dating
How old something is using radioactivity
Every 5730 years how much carbon 14 will decay to nitrogen 14
1/2
Fact
All living things have same amount of carbon 14 in them
Carbon 14 dating works for how long
Up to 50,000 years
Earth was formed during which era?
Precambrian
Differentiation
While earth was still molten the lightest material would float to top heaviest would float to bottom
What keeps earth hot
Radioactivity, meteors, gravitational contraction