20 Questions
Which of the following is a limitation of the biological species concept?
It cannot be applied to fossils or asexual organisms
What does the biological species concept emphasize?
Absence of gene flow
Which of the following is an example of gene flow between distinct species?
Grizzly bears and polar bears mating to produce 'grolar bears'
Why can't the biological species concept be applied to fossils?
Fossils do not reproduce
What is one limitation of the biological species concept?
It does not account for gene flow between distinct species
Which two species of bears can mate to produce 'grolar bears'?
Grizzly bears and polar bears
What is the main focus of the biological species concept?
Gene flow
Which of the following is a reason why gene flow between distinct species can occur?
Hybridization
What is an example of hybridization between two species of bears?
Grizzly bears and polar bears mating to produce 'grolar bears'
What does the biological species concept cannot be applied to?
Asexual organisms
Which species concept defines a species by structural features and does not rely on information about gene flow?
Morphological species concept
What is a disadvantage of the morphological species concept?
It relies on subjective criteria
Which species concept defines a species in terms of its ecological niche and emphasizes the role of disruptive selection?
Ecological species concept
What is a disadvantage of the ecological species concept?
It does not consider structural features
What is the process of speciation that occurs when populations are geographically isolated from each other?
Allopatric speciation
What is the process of speciation that occurs when populations are not geographically isolated?
Sympatric speciation
In allopatric speciation, gene flow is interrupted when a population is divided into geographically isolated __________.
Subpopulations
What can cause separated gene pools to diverge in allopatric speciation?
Mutation, natural selection, and genetic drift
What may arise as a by-product of genetic divergence in allopatric speciation?
Reproductive isolation
What is an example of behavioral isolation evolving in allopatric speciation?
The mosquitofish from ponds with and without predators
Study Notes
Biological Species Concept
- Emphasizes reproductive isolation between species
- Unable to be applied to fossils, as it requires observations of reproductive behaviors
- Limited in that it cannot be applied to species that are extinct or have no living members
Gene Flow and Hybridization
- Gene flow between distinct species can occur when there is a lack of reproductive barriers
- Example of hybridization: grizzly bears (Ursus arctos) and polar bears (Ursus maritimus) can mate to produce 'grolar bears'
Species Concepts
- Morphological species concept: defines a species by structural features and does not rely on information about gene flow
- Disadvantage: may not accurately reflect evolutionary relationships
- Ecological species concept: defines a species in terms of its ecological niche and emphasizes the role of disruptive selection
- Disadvantage: may not be able to distinguish between closely related species
Speciation
- Allopatric speciation: occurs when populations are geographically isolated from each other
- Process of speciation that occurs when a population is divided into geographically isolated groups, resulting in interrupted gene flow
- Divergence of separated gene pools can be caused by genetic drift, mutation, and natural selection
- May result in the formation of new species
- Behavioral isolation can evolve as a by-product of genetic divergence in allopatric speciation
Other Key Points
- Sympatric speciation: occurs when populations are not geographically isolated from each other
Test your knowledge on the limitations of the Biological Species Concept with this quiz. Explore why this concept cannot be applied to fossils or asexual organisms, and discover the instances where gene flow occurs between distinct species. Challenge yourself and expand your understanding of the boundaries of the Biological Species Concept.
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