Chapter 23 Flashcards
half-life
The time it takes for half of a given amount of a radioisotope to decay
radiometric dating
A dating method that uses measurements of certain radioactive isotopes to calculate the absolute ages in years of rocks and minerals
plate tectonics
The geological theory describing how Earth’s crust is broken into irregularly shaped plates of rocks that float on its semisolid mantle
continental drift
The long-term movement of continents as a result of plate tectonics
continuous distribution
A geographical distribution in which a species lives in suitable habitats throughout a geographical area
disjunct distributions
A geographical distributions in which populations of the same species or closely related species live in widely separated locations
Dispersal
The movement of organisms away from their place of origin
Vicariance
The fragmentation of a continuous geographical distribution by nonbiological factors
biotas
The total collection of organisms in a geographical region
biogeographical realms
A major region of Earth that is occupied by distinct evolutionary lineages of plants and animals
endemic species
A species that occurs in only one place on Earth
convergent evolution
The evolution of similar adaptations in distantly related organisms that occupy similar environments
biodiversity
The richness of living systems as reflected in genetic variability within and among species, the number of species living on Earth, and the variety of communities and ecosystems
adaptive radiation
A cluster of closely related species that are each adaptively specialized to a specific habitat or food source
adaptive zone
An environment or part of an environment that may be occupied by a group of species exploiting resources in a similar manner
extinction
The death of the last individual in a species or the last species in a lineage
background extinction rate
The average rate of extinction of taxa through time
mass extinctions
The disappearance of a large number of species in a relatively short period of geological time