Chapter 26 (Speciation) Flashcards
(21 cards)
allopatric speciation
The divergence of populations into different species by physical isolation of populations in different geographic areas.
allopatry
Condition in which two or more populations live in different geographic areas.
allopolyploid
The state of having more than two full sets of chromosomes (polyploidy) due to hybridization between different species.
autopolyploid
The state of having more than two full sets of chromosomes (polyploidy) due to a mutation that doubled the chromosome number.
biogeography
The study of how species and populations are distributed geographically.
biological species concept
The definition of a species as a population or group of populations that are reproductively isolated from other groups. Members of a species have the potential to interbreed in nature to produce viable, fertile offspring but cannot produce viable, fertile hybrid offspring with members of other species.
cryptic species
A species that cannot be distinguished from other species by easily identifiable morphological traits.
hybrid zone
A geographic area where interbreeding occurs between two species, sometimes producing fertile hybrid offspring.
monophyletic group
An evolutionary unit that includes an ancestral population and all of its descendants but no others. Also called a clade or lineage.
morphospecies concept
The definition of a species as a population or group of populations that have measurably different anatomical features from other groups. Also called morphospecies concept.
phylogenetic species concept
The definition of a species as the smallest monophyletic group in a phylogenetic tree.
polyploidy
The state of having more than two full sets of chromosomes.
postzygotic isolation
Reproductive isolation resulting from mechanisms that operate after mating of individuals of two different species occurs. The most common mechanisms are the death of hybrid embryos or reduced fitness of hybrids.
prezygotic isolation
Reproductive isolation resulting from mechanisms that operate after mating of individuals of two different species occurs. The most common mechanisms are the death of hybrid embryos or reduced fitness of hybrids.
reinforcement
In evolutionary biology, the natural selection for traits that prevent interbreeding between recently diverged species.
sister species
Closely related species, which occupy adjacent branches in a phylogenetic tree.
species
A distinct, identifiable group of populations that is thought to be evolutionarily independent of other populations and whose members can interbreed. Generally distinct from other species in appearance, behavior, habitat, ecology, genetic characteristics, etc.
subspecies
A population that has distinctive traits and some genetic differences relative to other populations of the same species but that is not distinct enough to be classified as a separate species.
sympatric speciation
The divergence of populations living within the same geographic area into different species as the result of their genetic (not physical) isolation
sympatry
Condition in which two or more populations live in the same geographic area, or close enough to permit interbreeding.
vicariance
The physical splitting of a population into smaller, isolated populations by a geographic barrier.
