Chapter 22: Speciation Flashcards
(23 cards)
Speciation
The process of species formation
Morphological species concept
The concept that all individuals of a species share measurable traits that distinguish them from individuals of other species.
Biological species concept
The definition of species based on the ability of populations to interbreed and produce fertile offspring.
Phylogenetic species concept
A concept that seeks to delineate species as the smallest group of populations that can be united by several derived characters.
Subspecies
A taxonomic subdivision of a species
Cline
A pattern of smoothie variation in a characteristic along a geographical gradient.
Reproductive isolating mechanism
A biological characteristic that prevents the gene pools of two species from mixing.
Prezygotic isolating mechanisms
A reproductive isolating mechanism that acts before the production of a zygote, or fertilized egg.
Postzygotic isolating mechanisms
A reproductive isolating mechanism that acts after zygote formation.
Ecological isolation
A prezygotic reproductive isolating mechanism in which species that live in the same geographical region occupy different habitats.
Temporal isolation
A prezygotic isolating mechanism in which species live in the same habitat but breed at different times of day or different times of year.
Behavioral isolation
A prezygotic reproductive isolating mechanism in which two species do not mare because of differences in courtship behavior, also known as ethnological isolation.
Mechanical isolation
A prezygotic reproductive isolating mechanism caused by differences in the structure of reproductive organs or other body parts.
Gametic isolation
A prezygotic reproductive isolating mechanism caused by incompatibility between the sperm of one species and the eggs of another, may prevent fertilization
Hybrid inviability
A postzygotic reproductive isolating mechanism in which a hybrid individual has a low probability of survival to reproductive age.
Hybrid sterility
A postzygotic reproductive isolating mechanism in which hybrid offspring cannot form functional gametes.
Hybrid breakdown
A postzygotic reproductive isolating mechanism in which hybrids are capable of reproducing, but their offspring have either reduced fertility or reduced viability.
Allopatric speciation
The evolution of reproductive isolating mechanisms between two populations that are geographically separated.
Hybrid zones
A geographical area where the hybrid offspring of two divergent populations or species are common.
Sympathetic speciation
Speciation that occurs without the geographical isolation of populations.
Polyploidy
The condition of having one or more extra copies of the entire haploid complement of chromosomes.
Autopolyploidy
The genetic condition of having more than two sets of chromosomes from the same parent species.
Unreduced gametes
A gamete that contains the same number of chromosomes as a somatic cell.
