Ch. 20 - History of Life Flashcards
1
Q
extinct
A
- term used to refer to a species that has died out and has no living members
2
Q
relative dating
A
- method of determining the age of a fossil by comparing its placement with that of fossils in other rock layers
3
Q
Index fossil
A
- distinctive fossil that is used to compare the relative age of fossils
4
Q
radiometric dating
A
- method for determining the age of a sample from the amount of a radioactive isotope to the non radioactive isotope of the same element in a sample
5
Q
half life
A
- length of time required for half of the radioactive atoms in a sample to decay
6
Q
geologic time scale
A
- timeline used to represent Earth’s history
7
Q
era
A
- major division of geologic time; usually divided into two or more periods
8
Q
period
A
- division of geologic time into which eras are subdivided
9
Q
plate tectonics
A
- geologic processes, such as continental drift, volcanoes, and earthquakes, resulting from plates movement
10
Q
macroevolutionary pattern
A
- changes in anatomy, phylogeny, and behavior that takes place in clodes larger than a single species
11
Q
background extinction
A
- extinction caused by slow and steady process of natural selection
12
Q
mass extinction
A
- event during which many species become extinct during a relatively short period of time
13
Q
gradualism
A
- the evolution of a species by gradual accumulation of small genetic changes over long periods of time
14
Q
punctuated equilibrium
A
- pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
15
Q
adaptive radiation
A
- process by which a single species or a small group of species evolves into several different forms that live in different ways
