Biol 345 Exam 3 ASU Questions and Answers
Speciation - Answer-the formation of new and distinct species in the course of evolution.
/.Biological Species Concept (BSC) - Answer-species are groups of actually or
potentially interbreeding populations that are reproductively isolated from other such
groups
- Does not require 100% reproductive isolation
- has limitations, ie asexual reproduction
/.reproductive isolation - Answer-Separation of species or populations so that they
cannot interbreed and produce fertile offspring
/.sister species - Answer-two species descended from a single ancestral species, and
are therefore one another's closest relatives.
/.alloparic speciation - Answer-The evolution of genetic barriers between populations
that are separated by a physical, geographic barrier. (speciation without gene flow) Can
originate either by vicariance or dispersal.
/.sympatric speciation - Answer-When when a single population splits into two
reproductively isolated populations while living together. (speciation with gene flow)
/.Phylogenetic Species Concept (PSC) - Answer-an irreducible (basal) cluster of
organisms diagnosably different from other such clusters, and within which there is a
parental pattern of ancestry and descent
/.ecological speciation - Answer-the evolution of reproductive barriers between
populations by adaptation to different environments or ecological niches
/.genetic conflict - Answer-occurs when an allele increases its own transmission to the
detriment of other alleles at the same or other loci
/.segregation distortion - Answer-unequal representation of alternate alleles in the
gametes, due to abnormalities of segregation during meiosis
/.Reinforcement - Answer-An event following a response that strengthens the tendency
to make that response.
/.prezygotic isolation - Answer-a barrier to successful breeding that occurs before
fertilization, such as differences in mating time or behavior
, /.postzygotic isolation - Answer-reproductive isolation that occurs after members of two
different species have mated and produced a hybrid offspring. Such hybrids are usually
unable to reproduce
/.parapatric speciation - Answer-An intermediate between the two other forms of
speciation. neighboring populations of a single species that exchange genes
nevertheless diverge into two species. (speciation with gene flow)
/.speciation with gene flow - Answer-sympatric speciation and parapatric speciation
involve speciation with gene flow, while allopatric speciation does not
/.Vicariance - Answer-The physical splitting of a population into smaller, isolated
populations by a geographic barrier.
/.dispersal - Answer-the movement of organisms from one place to another
/.secondary contact - Answer-In allopatric speciation, isolating mechanisms evolve in
geographically separated populations. They play a role in restricting gene flow only if
the populations come back together, an event called secondary contact. This often
happens as the range of one or both incipient species expands. The newly formed
species can then coexist as distinct populations if they are sufficiently reproductively
isolated.
/.assortatively - Answer-red birds tend to mate with red birds, and blue birds with blue
birds. (Assortative mating could arise, for example, if young birds imprint on the color of
their parents.)
/.speciation trait - Answer-a trait that causes both ecological divergence and
reproductive isolation between the incipient species
/.reproductive isolating barriers (RIBs) or isolating mechanisms - Answer-Gene flow
between biological species is prevented by biological differences
/.Suppose the Phylogenetic Species Concept (PSC) were preferred over other species
concepts, such as the Biological Species Concept (BSC). What would be the
implications for:
(a) discourse on the evolutionary mechanisms of speciation - Answer-In contrast to the
biological species concept (which focuses on reproductive isolation), the phylogenetic
species concept focuses on clusters of diagnostically distinct organisms that share
common ancestry.
Mechanisms of reproductive isolation are important to the BSC (such as whether
isolating barriers are premating, prezygotic, or postzygotic). If the PSC were used, there
would be less focus on reproductive isolation and greater emphasis on the identification
Speciation - Answer-the formation of new and distinct species in the course of evolution.
/.Biological Species Concept (BSC) - Answer-species are groups of actually or
potentially interbreeding populations that are reproductively isolated from other such
groups
- Does not require 100% reproductive isolation
- has limitations, ie asexual reproduction
/.reproductive isolation - Answer-Separation of species or populations so that they
cannot interbreed and produce fertile offspring
/.sister species - Answer-two species descended from a single ancestral species, and
are therefore one another's closest relatives.
/.alloparic speciation - Answer-The evolution of genetic barriers between populations
that are separated by a physical, geographic barrier. (speciation without gene flow) Can
originate either by vicariance or dispersal.
/.sympatric speciation - Answer-When when a single population splits into two
reproductively isolated populations while living together. (speciation with gene flow)
/.Phylogenetic Species Concept (PSC) - Answer-an irreducible (basal) cluster of
organisms diagnosably different from other such clusters, and within which there is a
parental pattern of ancestry and descent
/.ecological speciation - Answer-the evolution of reproductive barriers between
populations by adaptation to different environments or ecological niches
/.genetic conflict - Answer-occurs when an allele increases its own transmission to the
detriment of other alleles at the same or other loci
/.segregation distortion - Answer-unequal representation of alternate alleles in the
gametes, due to abnormalities of segregation during meiosis
/.Reinforcement - Answer-An event following a response that strengthens the tendency
to make that response.
/.prezygotic isolation - Answer-a barrier to successful breeding that occurs before
fertilization, such as differences in mating time or behavior
, /.postzygotic isolation - Answer-reproductive isolation that occurs after members of two
different species have mated and produced a hybrid offspring. Such hybrids are usually
unable to reproduce
/.parapatric speciation - Answer-An intermediate between the two other forms of
speciation. neighboring populations of a single species that exchange genes
nevertheless diverge into two species. (speciation with gene flow)
/.speciation with gene flow - Answer-sympatric speciation and parapatric speciation
involve speciation with gene flow, while allopatric speciation does not
/.Vicariance - Answer-The physical splitting of a population into smaller, isolated
populations by a geographic barrier.
/.dispersal - Answer-the movement of organisms from one place to another
/.secondary contact - Answer-In allopatric speciation, isolating mechanisms evolve in
geographically separated populations. They play a role in restricting gene flow only if
the populations come back together, an event called secondary contact. This often
happens as the range of one or both incipient species expands. The newly formed
species can then coexist as distinct populations if they are sufficiently reproductively
isolated.
/.assortatively - Answer-red birds tend to mate with red birds, and blue birds with blue
birds. (Assortative mating could arise, for example, if young birds imprint on the color of
their parents.)
/.speciation trait - Answer-a trait that causes both ecological divergence and
reproductive isolation between the incipient species
/.reproductive isolating barriers (RIBs) or isolating mechanisms - Answer-Gene flow
between biological species is prevented by biological differences
/.Suppose the Phylogenetic Species Concept (PSC) were preferred over other species
concepts, such as the Biological Species Concept (BSC). What would be the
implications for:
(a) discourse on the evolutionary mechanisms of speciation - Answer-In contrast to the
biological species concept (which focuses on reproductive isolation), the phylogenetic
species concept focuses on clusters of diagnostically distinct organisms that share
common ancestry.
Mechanisms of reproductive isolation are important to the BSC (such as whether
isolating barriers are premating, prezygotic, or postzygotic). If the PSC were used, there
would be less focus on reproductive isolation and greater emphasis on the identification
