2.3: The Origin of Species

Principles of Biology II, OL ed · LibreTexts

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    From LibreTexts, under CC BY 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Learning Objectives
    • Define species and describe how scientists identify species as different
    • Describe genetic variables that lead to speciation
    • Identify prezygotic and postzygotic reproductive barriers
    • Explain allopatric and sympatric speciation
    • Describe adaptive radiation
    • Explain the two major theories on rates of speciation

    • 2.3.1: Species Defined
      A biological species is defined as a group of individuals that, in nature, are able to mate and produce viable, fertile offspring. There are other definitions of species but, according to the biological definition, one species is distinguished from another when, in nature, it is not possible for matings between individuals from each species to produce fertile, living offspring.
    • 2.3.2: Speciation
      Speciation is an event in which a single species may branch to form two or more new species.
    • 2.3.3: Rates of Speciation and Extinction
      Scientists around the world study speciation, documenting observations both of living organisms and those found in the fossil record. As their ideas take shape and as research reveals new details about how life evolves, they develop models to help explain rates of speciation. In terms of how quickly speciation occurs, two patterns are currently observed: the gradual speciation model and the punctuated equilibrium model.

    This page titled 2.3: The Origin of Species was last modified on Fri, 02 Jun 2023 04:10:56 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by TRU - OL.