Species and speciation #14 Flashcards
Define the term “species” according to the biological species concept.
A species is a group of actually or potentially interbreeding populations that are reproductively isolated from other such groups.
Explain why reproductive isolation is an important component of the biological species concept.
Reproductive isolation is important because it allows us to distinguish between different gene pools, which is necessary for defining separate species. It also reflects the evolution of biological barriers to gene flow, which is the process of speciation.
Describe the limitations of the biological species concept.
The biological species concept does not work for asexually reproducing species, and it is difficult to test in the lab. It also assumes a clear distinction between interbreeding and isolation, whereas in reality, there is often a continuum of gene flow between populations.
Define the phylogenetic species concept.
The phylogenetic species concept defines a species as an irreducible (basal) cluster of organisms that is diagnosably different from other such clusters, and within which there is a parental pattern of ancestry and descent.
Define the morphological species concept.
The morphological species concept defines a species based on physical similarities. However, this approach can be problematic because of convergent evolution.
Explain why species concepts are important for conservation, biosecurity, land management, biodiversity, and economic and medicinal uses.
Understanding and defining species is important for managing and conserving natural resources, protecting against invasive species, and preserving biodiversity. It also helps to identify potential economic and medicinal uses of different species.
Define speciation.
Speciation is the process by which one species gives rise to two.
Describe the different types of speciation.
The different types of speciation include allopatric speciation (when populations are geographically isolated), sympatric speciation (when populations are not geographically isolated), and parapatric speciation (when populations are partially isolated).
Explain the various causes of speciation.
Speciation can be caused by a range of factors, including geographical isolation, ecological factors, genetic drift, and hybridization.
Define a hybrid zone.
A hybrid zone is an area where two different species or subspecies come into contact and interbreed, leading to a mixture of gene pools.
Describe prezygotic barriers to gene flow.
Prezygotic barriers are factors that prevent two different species or populations from successfully mating and producing offspring. These barriers can include separation by habitat, pollination vectors, mating timing, mating preference, and gamete incompatibility.
Describe postzygotic barriers to gene flow.
Postzygotic barriers are factors that reduce the likelihood of gene exchange between populations after mating has occurred. These barriers can include reduced hybrid viability or fertility, and incompatibilities between genes inherited from the two parents.
