Geographic area
________ may have variation so that some members of a population may diverge and occupy different local environments that are continuous with each other.
Gene flow
________ between populations holds the phenotype of a population together.
Cladogenetic speciation
________: occurs when a population is different enough from its ancestral species so that no genetic exchange can occur between them.
Drawback
________- different groups of bacteria sometimes display very similar growth characteristics, and even the same species may show great variation in the growth conditions it will tolerate.
Sympatric speciation
________: occurs when members of a species that are within the same range diverge into two or more different species even though there are no physical barriers to interbreeding.
Morphological traits
________: physical characteristics of an organism.
Adaptive radiations
________ can occur when organisms colonize new environments with little competition.
Fusion
________: if hybrids are as fit as parents, there can be substantial gene flow between species.
Reproductive isolation
________: prevents one species from successfully interbreeding with other species.
Presence of a variety of open ecological niches
________ provides opportunity for sympatric speciation by disruptive selection.
extensive gene flow
Stability: ________ from outside the hybrid zone can overwhelm selection for increased reproductive isolation inside the hybrid zone.
Hybrid zones
________ reveal factors that cause reproductive isolation.
Hybrids
________: the result of mating between species with incomplete reproductive barriers.
Reproductive isolation
________ is a result of genetic factors that cause offspring to rely upon resources not used by previous generations.
Adaptive radiation
________: produced from a combination of allopatric and sympatric speciation; the rapid evolution of diversely adapted species from a common ancestor.
Morphological traits
physical characteristics of an organism
Biological species concept
states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations
Reproductive isolation
prevents one species from successfully interbreeding with other species
Drawback
different groups of bacteria sometimes display very similar growth characteristics, and even the same species may show great variation in the growth conditions it will tolerate
Biological species concept
species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring, but cannot successfully interbreed with members of other species
Evolutionary lineage concept
species should be defined based on the separate evolution of lineages
Cladogenetic speciation
occurs when a population is different enough from its ancestral species so that no genetic exchange can occur between them
Sympatric speciation
occurs when members of a species that are within the same range diverge into two or more different species even though there are no physical barriers to interbreeding
Hybrid zone
a region in which members of different species mate and produce hybrids
Hybrids
the result of mating between species with incomplete reproductive barriers
Fusion
if hybrids are as fit as parents, there can be substantial gene flow between species
Stability
extensive gene flow from outside the hybrid zone can overwhelm selection for increased reproductive isolation inside the hybrid zone
Adaptive radiation
produced from a combination of allopatric and sympatric speciation; the rapid evolution of diversely adapted species from a common ancestor