Chapter 22 Flashcards
A group of individuals that can exchange genetic material through interbreeding to produce fertile offspring.
Species
As described by Ernst Mayr, the concept that “species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups.” The BSC is the most widely used and accepted definition of a species, but cannot be applied to Bacteria or Archaea.
biological species concept (BSC)
Describes populations that have not yet diverged as separate species but whose genetic differences are extensive enough that the hybrid offspring they produce have reduced fertility or viability compared with offspring produced by crosses between individuals within each population.
partially reproductively isolated
The idea that members of the same species usually look like each other more than like other species.
morphospecies concept
Species that contain populations that are reproductively isolated from each other but can exchange genetic material through other, linking populations.
Ring Species
Interbreeding between two different varieties or species.
Hybridization
A complete description of the role a species plays in its environment.
Ecological Niche
The concept that there is a one-to-one correspondence between a species and its niche.
ecological species concept (ESC)
The idea that members of a species all share a common ancestry and a common fate.
phylogenetic species concept (PSC)
Describes factors that prevent the fertilization of an egg.
pre-zygotic isolation
Describes factors that cause the failure of the fertilized egg to develop into a fertile individual.
post-zygotic isolation
Describes individuals that only mate with other individuals on the basis of specific courtship rituals, songs, and other behaviors.
behaviorally isolated
Incompatibility between the gametes of two different species.
gametic isolation
Structural configuration of the genitalia that prevents mating with another species.
mechanical incompatibility
Pre-zygotic isolation between individuals that are reproductively active at different times.
temporal isolation
Spatial segregation of individuals.
geographic isolation
Pre-zygotic isolation between individuals that specialize ecologically in different ways
ecological isolation
Describes populations that have not yet diverged as separate species but whose genetic differences are extensive enough that the hybrid offspring they produce have reduced fertility or viability compared with offspring produced by crosses between individuals within each population
partially reproductively isolated
Describes populations that are geographically separated from each other.
Allopatric
Allopatric populations that have yet to evolve even partial reproductive isolation but which have acquired population-specific traits.
Subspecies
The process in which some individuals colonize a distant place far from the main source population.
Dispersal
The process in which a geographic barrier arises within a single population, separating it into two or more isolated populations.
Vicariance
A specific kind of allopatric speciation in which a few individuals from a mainland population disperse to a new location remote from the original population and evolve separately.
peripatric speciation
The central population of a species.
mainland population
An isolated population.
island population
A period of unusually rapid evolutionary diversification in which natural selection accelerates the rates of both speciation and adaptation in a single lineage.
adaptive radiation
A process in which two groups of organisms speciate in response to each other and at the same time, producing matching phylogenies.
co-speciation
Describes populations that are in the same geographic location.
sympatric
Speciation that occurs in a single generation.
instantaneous speciation
The condition of having more than two complete sets of chromosomes in the genome.
Polyploidy
The process by which diverging populations undergo natural selection in favor of enhanced pre-zygotic isolation to prevent the production of inferior hybrid offspring.
reinforcement of reproductive isolation (reinforcement)
What are some different types of pre- and post-zygotic barriers and why are they important?
Pre-zygotic factors prevent fertilization from taking place, whereas post-zygotic factors result in the failure of the fertilized egg to develop into a fertile individual.
Given a group of organisms, describe how you would test whether they all belong to one species or whether they belong to two separate species?
b
Name two types of organisms that do not fit easily into the biological species concept. What species concept would work best for these organisms?
b
Explain how ecological considerations can help inform whether or not a group of organisms represents a single species.
b
Differentiate between allopatric and sympatric speciation, and state which is thought to be more common and why.
b
Describe the random and nonrandom processes that result in speciation. Can both be considered evolution? Why or why not?
b
