chapter 22 ~ speciation Flashcards
The process of species formation.
Speciation
The concept that all individuals of a species share measurable traits that distinguish them from individuals of other species.
Morphological species concept
The definition of species based on the ability of populations to interbreed and produce fertile offspring.
Biological species concept
A concept that seeks to delineate species as the smallest group of populations that can be united by shared derived characters.
Phylogenetic species concept
A taxonomic subdivision of a species.
Subspecies
A species with a geographical distribution that forms a ring around uninhabitable terrain.
Ring species
A pattern of smooth variation in a characteristic along a geographical gradient.
Cline
A biological characteristic that prevents the gene pools of two species from mixing.
Reproductive isolating mechanisms
An organism produced by a mating between parents of different species or subspecies.
Hybrid
A reproductive isolating mechanism that acts before the production of a zygote, or fertilized egg.
Prezygotic isolating mechanisms
A reproductive isolating mechanism that acts after zygote formation.
Postzygotic isolating mechanisms
A prezygotic reproductive isolating mechanism in which species that live in the same geographical region occupy different habitats.
Ecological isolation
A prezygotic reproductive isolating mechanism in which species live in the same habitat but breed at different times of day or different times of year.
Temporal isolation
A prezygotic reproductive isolating mechanism in which two species do not mate because of differences in courtship behavior; also known as ethological isolation.
Behavioral isolation
A prezygotic reproductive isolating mechanism caused by differences in the structure of reproductive organs or other body parts.
Mechanical isolation
A prezygotic reproductive isolating mechanism caused by incompatibility between the sperm of one species and the egg of another; may prevent fertilization.
Gametic isolation
A postzygotic reproductive isolating mechanism in which a hybrid individual has a low probability of survival to reproductive age.
Hybrid inviability
A postzygotic reproductive isolating mechanism in which hybrid offspring cannot form functional gametes.
Hybrid sterility
A postzygotic reproductive isolating mechanism in which hybrids are capable of reproducing, but their offspring have either reduced fertility or reduced viability.
Hybrid breakdown
The evolution of reproductive isolating mechanisms between two populations that are geographically separated.
Allopatric speciation
A group of closely related species recently descended from a common ancestor.
Species cluster
The reestablishment of geographical overlap after a barrier that separated allopatric populations no longer keeps them apart.
Secondary contact
Merger of two populations into one after the establishment of secondary contract.
Species fusion
A geographical area where the hybrid offspring of two divergent populations or species are common.
Hybrid zones
