Chapter 22 - Speciation Flashcards
What is the morphological species concept?
The concept that all individuals of a species share measurable traits that distinguish them from individuals of other species.
What is speciation?
The process of species formation.
What is the biological species concept?
The definition of species based on the ability of populations to interbreed and produce fertile offspring. In other words, if members of two populations interbreed and produce fertile offspring, they belong to the same species.
What is the phylogenetic species concept?
A concept that seeks to delineate species as the smallest aggregate population that can be united by shared derived characters.
What is a ring species?
A species with a geographical distribution that forms a ring around uninhabitable terrain.
What is a cline?
A pattern of smooth variation in a characteristic along a geographical gradient.
What is a reproductive isolating mechanism?
A biological characteristic that prevents the gene pools of two species from mixing.
What are prezygotic isolating mechanisms?
A reproductive isolating mechanism that acts before the production of a zygote.
Species live in different habitats (ecological), breed at different times (temporal), cannot communicate (behavioral), cannot physically mate (mechanical), or have nonmatching receptors on gametes (gametic).
What are postzygotic isolating mechanisms?
A reproductive isolating mechanism that acts after zygote formation.
Hybrid offspring doesn’t complete development (inviability), cannot produce gametes (sterility), or have reduced survival or fertility (breakdown).
What is allopatric speciation?
The evolution of reproductive isolating mechanisms between two populations that are geographically separated. Genetic divergence leads to speciation through mutation, genetic drift, and natural selection.
It occurs in two stages:
1) Two populations become geographically separated, preventing gene flow.
2) They accumulate genetic differences that isolate them reproductively.
What is parapatric speciation?
Speciation between populations with adjacent geographical distributions. Chromosome alterations causes the speciation.
What is sympatric speciation?
Speciation that occurs without the geographical isolation of populations. Reproductive isolation evolves between distinct subgroups that arise within one population.
What is polyploidy?
The condition of having one or more extra copies of the entire haploid complement of chromosomes. Sympatric speciation in plants occurs because of polyploidy.
