Macroevolution

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