After Midterms Flashcards
(26 cards)
when did taxonomy emerge?
1600s
what is the phylogenetic species concept?
species are the smallest possible groups whose members are descended from a common ancestor and who all possess defining or derives characteristics that distinguish them from other such groups
what is the biological species concept? (aka Mayr’s definition)
species are groups of actually (or potentially) interbreeding natural populations that are reproductively isolated from other such groups.
what is a metapopulation?
a group of spatially separated populations of the same species that interact at some level
what is the general lineage species concept?
species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool and therefore the same evolutionary lineage
which species concept is most useful for identifying separate species?
general lineage species concept
what are isolating barriers?
an aspect of the environment, genetics, behaviour, physiology, or ecology of a species. Can be geographical or reproductive
what is speciation?
the evolutionary process by which new species arise.
what do isolating barriers block?
gene flow
what is allopatry?
geographic separation
when does allopatry occur?
when populations are in separate, nonoverlapping geographic areas
according to the biological species concept, is allopatry enough to warrant the dividing of 2 populations?
no, must also be unlikely or unable to interbreed
when does sympatry occur?
when populations are in the same geographic area.
what are the 3 categories of reproductive barriers?
finding a mate, forming a zygote, successfully developing reproductively viable offspring
when does gametic incompatibility occur?
when sperm or pollen from one species fails to penetrate and fertilize the egg or ovule of another species
what is a prezygotic reproductive barrier?
an aspect of the genetics, behaviour, physiology, or ecology of a species that prevents sperm from one species from fertilizing eggs of another species.
Reduce likelihood that a zygote will form
what is a postzygotic barrier?
an aspect of the genetics, behaviour, physiology, or ecology of a species that prevents hybrid zygotes from successfully developing and reproducing themselves.
what is a Bateson-Dobzhansky-Muller incompatibility?
a genetic incompatibility in hybrid offspring arising from epistatic interactions between 2 or more loci
does the evolution of new barriers to reproduction evolve gradually or all at once?
gradually, in a series of steps.
what is allopatric speciation?
the evolution of new species after populations have been separated geographically, preventing gene flow between them.
what is sympatric speciation?
the evolution of new species within a contiguous population that still has extensive gene flow
what is parapatric speciation?
the evolution of new species within a spatially extended population that still has some gene flow
what is isolation by distance?
a pattern in which populations that live in close proximity are genetically more similar to each other than populations that live father apart
what is ecological speciation?
the evolution of reproductive barriers between populations by adaption to different environments or ecological niches
