Chapter 14 - The Origin of Species Flashcards
Speciation
The evolution of a new species.
Biological species concept
Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups.
Species
A group of populations whose members have the potential to interbreed and produce viable, fertile offspring.
Reproductive isolation
The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.
Hybrid
Offspring that results from the mating of individuals from two different species or from two true-breeding varieties of the same species; an offspring of two parents that differ in one or more inherited traits; an individual that is heterozygous for one or more pairs of genes.
Morphological species concept
A definition of species in terms of measurable anatomical criteria.
Morphological species concept
A definition of species in terms of measurable anatomical criteria.
Ecological species concept
A definition of species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment.
Phylogenetic species concept
A definition of species as the smallest group of individuals that shares a common ancestor, forming one branch on the tree of life.
Prezygotic barriers
A reproductive barrier that impedes mating between species or hinders fertilization if mating between two species is attempted. Includes temporal, habitat, behavioral, mechanical, and gametic isolation.
Postzygotic barriers
A reproductive barrier that prevents hybrid zygotes produce by two different species from developing into viable, fertile adults. Includes reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown.
Allopatric speciation
The formation of new species in populations that are geographically isolated from one another.
Sympatric speciation
The formation of new species in populations that live in the same geographic area.
Polyploid
An organism that has more than two complete sets of chromosomes as a result of an accident of cell division.
Adaptive radiation
Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill new or vacant ecological roles in their communities.
