Chapter 26- Speciation Flashcards
Species
An evolutionarily independent population or groyp of populations.
Speciation
A splitting event that creates two or more distinct species from a single ancestral group.
Genetic Isolation
The isolation of a population’s genes due to a lack of gene flow.
Genetic Divergence
When selection, genetic drift, and mutation act independently upon isolated populations.
Biological Species Concept
Species are indentified by reproductive isolation. Populations are of different species if they are unable to produce offspring with each other.
Reproductive Isolation
The inability of two isolated populations to interbreed.
Prezygotic Isolation
Prevents individuals from different species from mating.
Postzygotic Isolation
The offspring of matings between members of different species do not survive or reproduce.
Temporal Isolation
Populations are isolated because they breed at different times.
Habitat Isolation
Populations are isolated because they breed in different habitats.
Behavioral Isolation
Populations do not interbreed because their courtship displays differ.
Gametic Barrier
Matings fail because eggs and sperm are incompatible.
Mechanical Isolation
Matings fail because male and female reproductive structures are incompatible.
Hybrid Viability
Hybrid offspring do not develop normally and die as embryos.
Hybrid Sterility
Hybrid offspring mature but are sterile as adults.
Morphospecies Concept
Species are identified by differences in size, shape, or other morphological features.
Cryptic Species
Species that differ in traits other than morphology.
Morphology
The physical form and appearance of an individual.
Phylogenetic Species Concept
Identifies evolutionarily independent lineages by reconstructing the evolutionary history of populations.
Monophyletic Group/Clade/Lineage
Consists of an ancestral population, all of its descendents, and only those descendents.
Synapomorphy
A trait found in certain groups of organisms that exists in no others.
Common Ancestry
The sharing of an ancestral species.
Phylogenetic Trees
A branching diagram of the connections between ancestral and descendent species.
Phylogeny
A family tree of ancestral species and their descendents.
Subspecies
Populations that live in discrete geographic areas and have distinguishing features but not distinct enough to be considered a separate species.
Endangered Species Act
A law whose goal is to prevent the extinction of species.
Allopatry
When populations live in different areas.
Allopatric Speciation
Speciation that begins with physical isolation.
Vicariance
A physical splitting of habitat.
Dispersal
The spreading of a population to a new habitat, where they colonize it and found a new population.
Biogeography
The study of how species and populations are are distributed geographically.
Colonization
The migration of a population to a new area where a new population is founded.
Sympatry
When populations live close enough to make interbreeding possible.
Sympatric Speciation
Speciation that occurs even though gene flow is possible.
Disruptive Speciation
Natural selection that selects for the extreme phenotypes on the phenotypic scale.
Polyploidy
The condition that mutant individuals have more than two sets of chromosomes.
Nondisjunction
The failure of chromosomes to split during meiosis or mitosis.
Triploid
Having three chromosomes.
Tetraploid
Having four chromosomes instead of two.
Autopolyploidy
Individuals with twice the amount of chromosomes from the same species.
Allopolyploid
Individuals with double the number of chromosomes from parents of two different species.
Self Fertilization
When a parent can fertilize their own eggs.
Reinforcement
Selection for traits that isolate populations because hybrid offspring are a wasted effort of the parents and individuals who do not interbreed produce more viable offspring.
Hybrid Zone
A geographic area where interbreeding occurs and hybrid offspring are common.
Mitochondrial DNA
DNA that is maternally inherited in most animals and plants and can be used to determine the parent species of hybrids.
Fusion of Populations
Two populations freely interbreed
Backcrossing
Mating hybrids with a member of one of their parent species.
Secondary Contact
When two populations come into contact with each other.
Hybridization
The creation of hybrids between two species.