Macroevolution 2

Question 1

standing diversity

Answer 1

the number of species (or other taxonomic unit) present in a particular area at a given time

Question 2

Origination

Answer 2

the emergence of a new species or a new trait within a population or lineage. This can occur through various mechanisms such as mutation, genetic recombination, and natural selection, leading to the origination of novel genetic traits or species

Question 3

Extinction

Answer 3

the complete disappearance or cessation of a species, group of organisms, or a lineage

Question 4

adaptive radiation

Answer 4

an evolutionary lineage that has undergone exceptionally rapid diversification into a variety of lifestyles or ecological niches

Question 5

Cambrian Explosion

Answer 5

The rapid diversification of multicellular life that took place during the Cambrian period

Question 6

background extinction

Answer 6

normal rate of extinction for a taxon or biota

Question 7

mass extinction

Answer 7

describes a statistically significant departure from background extinction rates that results in a substantial loss of taxonomic diversity

Question 8

Sepkoski’s curve

Answer 8

representing how marine fauna diversity has varied over time from the Cambrian through Tertiary period, with the “big five” mass extinctions (Ordovician, Devonian, Guadalupian/Permian, Triassic, Cretaceous)

Question 9

Anagenesis

Answer 9

wholesale transformation of a lineage from one form to another. In macroevolutionary studies, anagenesis is considered to be an alternative to lineage splitting or speciation

Question 10

Cladogenesis

Answer 10

the evolutionary process by which new species arise. Speciation causes one evolutionary lineage to split into two or more lineages (cladogenesis)

Question 11

punctuated equilibria

Answer 11

a model of evolution that proposes that most species undergo relatively little change for most of their geological history. These periods of stasis are punctuated by brief periods of rapid morphological change, often associated with speciation

Question 12

Stasis

Answer 12

a period or state of inactivity or equilibrium

Question 13

sympatric speciation

Answer 13

occurs if some individuals begin to exploit a new niche, and mate only with others that do the same. Eventually the two groups will diverge and become separate species

Question 14

allopatric speciation

Answer 14

the evolution of new species after populations have been separated geographically, preventing gene flow between them OR Speciation that results when reproductive isolation occurs because of the interposition of (or crossing of) a physical geographic barrier such as a river. (Contrast with sympatric speciation.