Flashcards in Unit 2 Test Deck (28)
# of mass extinctions
percentage of extinct species
no longer in existance
what do paleontologist study
What causes a mass extinction
Climate Change, VolCANOES, astroids
Evidence of volcanoes/astroids
What does Carbon 12 mean
Carbon has a mass number of 12
helium nucleus (2 protons and electrons) 4/2He
an electron 0/-1e
Energy 0/0 weird Y
the isotope you have before the nuclear decay
the isotope you have after the nuclear decay
time required for a particle to reduce to half its initial value.
basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom, each layer being younger than the one beneath it and older than the one above it.
law of superposition
the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age).
a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when exactly they were formed.
crieteria for a good index fossil
distinctive, widespread, abundant and limited in geologic time.
the idea that all continents were once connected
Evidance for Pangea
1. Fit of the Continents
2. Past Climate Belts and Distribution of Fossils
3. Matching Rock Types
When plates slide pass each other
a place where an organism lives