Chapter 22 Flashcards
Speciation
The process by which one species splits into two or more species.
Macroevolution
Broad patterns of evolutionary change above the species level.
Biological Species Concept
A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.
Reproductive isolation
The existence of biological barriers that impede two members of two species from producing viable, fertile offspring.
Hybrids
The offspring of crosses between different species.
Prezygotic barriers
Block fertilization from occurring.
Postzygotic Barriers
Prevent the hybrid zygote from developing into a viable, fertile adult.
Morphological Species Concept
Defines a species by structural features.
Ecological Species Concept
Defines a species in terms of its ecological niche.
Allopatric Speciation
Occurs when populations are geographically isolated from one another.
Polyploidy
The presence of extra sets of chromosomes due to accidents during cell division.
Autopolyploid
An individual with two or more sets of chromosomes derived from one species.
Allopolyploid
A species with multiple sets of chromosomes derived from different species. Can mate with each other but not the parent species.
Hybrid Zone
A region in which members of different species mate and produce hybrids.
Reinforcement
Occurs when hybrids are less fit than the parent species.
