Chapter 13- Speciation Flashcards
Species are the smallest possible groups who members are descended from a common ancestor and who all possess defining or derived characteristics that distinguish them from other such groups
Phylogenetic Species Concept
Species are groups of actually (or potentially) interbreeding natural populations that are reproductively isolated from other such groups
Biological Species Concept
A group of spatially separated populations of the same species that interact at some level (e.g., exchange alleles).
Metapopulation
Species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool, and therefore, the same evolutionary lineage.
General Lineage Species Concept
An aspect of the environment, genetics, behavior, physiology, or ecology of a species that reduces or impedes gene flow from individuals of other species. This can be geographic or reproductive.
Isolating Barrier
The evolutionary process by which new species arise. It causes one evolutionary lineage to split into two or more lineages (cladogenesis).
Speciation
Occurs when populations are in separate, non-overlapping geographic areas (i.e., they are separated by geographic barriers to gene flow).
Allopatry
Occurs when populations are in the same geographic area.
Sympatry
Occurs when sperm or pollen from one species fails to penetrate and fertilize the egg of another species.
Genetic Incompatibility
Occurs when reproductive barriers prevent or strongly limit reproduction between populations. The result is that few or no genes are exchanged between the populations.
Reproductive Isolation
Occurs when sperm or pollen from one species fails to penetrate and fertilize the egg of another species.
Gametic Incompatibility
Aspects of the genetics, behavior, physiology, or ecology of a species that prevent fertilized zygotes from successfully developing and reproducing themselves.
Post-zygotic Reproductive Barriers
Aspects of the genetics, behavior, physiology, or ecology of a species that prevent sperm from one species from fertilizing eggs of another species. These reduce the likelihood that a zygote will form.
Pre-zygotic Reproductive Barriers
The increase of reproductive isolation between populations through selection against hybrid offspring.
Reinforcement
Populations that live nearby are genetically more similar to each other than populations that live farther apart.
Isolation by Distance
A connected series of populations (each of which can interbreed with its neighboring populations) that have diverged sufficiently across their ranges so that the populations at the ends of the series are too different to interbreed.
Ring Species
The evolution of reproductive barriers between populations by adaptation to different environments or ecological niches.
Ecological Speciation
Polyploidy (more than two paired chromosomes) resulting from interspecific hybridization.
Allopolyploidy
Polyploidy arising within a species
Autopolyploidy
Groups of organisms that are genetically distinct and do not interbreed, but are morphologically almost indistinguishable.
Cryptic Species
