Speciation is the evolutionary process by which new biological species arise, enhancing biodiversity. It occurs when populations become reproductively isolated, leading to genetic divergence. This isolation can be due to geographic barriers, behavioral changes, or temporal shifts in mating. The text explores different speciation types—allopatric, sympatric, and parapatric—and the role of genetic drift and isolating mechanisms in species formation.
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Biological species are defined as groups of interbreeding natural populations
Causes of isolation
Reproductive isolation is essential for speciation and can be caused by physical barriers, behavioral changes, or temporal differences in mating periods
Importance of isolation
Isolation allows for independent evolution and prevents gene flow between populations
Speciation contributes to biodiversity and occurs when populations become reproductively isolated and undergo genetic divergence
Allopatric speciation occurs when populations are geographically isolated and undergo independent evolutionary changes
Sympatric speciation occurs when new species evolve from a single ancestral species while inhabiting the same geographic region
Parapatric speciation occurs when populations are distributed across a continuous range and mate more frequently within localized areas, leading to distinct populations and potential new species
Genetic drift, the random fluctuation of allele frequencies, can contribute to speciation by creating genetic differences between populations
Prezygotic mechanisms
Prezygotic mechanisms, such as differences in mating behaviors or physical incompatibilities, prevent different species from interbreeding
Postzygotic mechanisms
Postzygotic mechanisms, like hybrid inviability or infertility, ensure that genetic differences between species are not diluted by gene flow
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______ is the evolutionary process by which new biological species emerge, contributing to biodiversity.
Speciation
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Types of reproductive isolation mechanisms
Physical barriers, behavioral changes, temporal mating differences
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Example of geographic isolation leading to speciation
River changes course, separates populations, results in allopatric speciation
