1 / 26

Species concept

Species concept. Different species usually form clusters of phenotypes. Length. Mass. Chronospecies. Evolutionary species. Species concepts. What is a species? What are the criteria for defining a species?.

gada
Download Presentation

Species concept

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Species concept

  2. Different species usually form clusters of phenotypes Length Mass

  3. Chronospecies Evolutionary species

  4. Species concepts What is a species? What are the criteria for defining a species?

  5. Species consist of interbreeding populations that evolve independently of other populations

  6. Species concepts Biological species concept Phylogenetic species concept Morphospecies concept

  7. Species concepts Biological species concept - BSC species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups

  8. Species concepts Biological species concept - BSC species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups Problems with BSC -asexual organisms -hybridization

  9. Species concepts Phylogenetic species concept - PSC a species is a monophyletic group composed of the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent

  10. Species concepts Phylogenetic species concept - PSC a species is a monophyletic group composed of the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent Problems with PSC -quantifying synapomorphies

  11. Species concepts Morphospecies concept - MSC species are statistically distinguishable from others based upon an analysis of their morphological characteristics

  12. Species concepts Morphospecies concept - MSC species are statistically distinguishable from others based upon an analysis of their morphological characteristics Problems with MSC -arbitrary -leads to cryptic species

  13. Species concepts Biological species concept Phylogenetic species concept Morphospecies concept Beware the Procrustes fallacy!

  14. Reliable criteria for identifying species are essential for preserving biodiversity

  15. Indian elephant African elephant

  16. African forest elephant Indian elephant African elephant

  17. The speciation process begins when gene flow is disrupted and populations become genetically isolated

  18. Barriers to gene flow Prezygotic barriers 1 potential mates do not meet temporal isolation, habitat isolation 2 behavioral isolation 3 mechanical isolation 4 gametic incompatibility

  19. Barriers to gene flow Prezygotic barriers 1 potential mates do not meet temporal isolation, habitat isolation 2 behavioral isolation 3 mechanical isolation 4 gametic incompatibility Postzygotic barriers 1 zygotic mortality 2 hybrid inviability 3 hybrid sterility 4 F2 hybrid breakdown

  20. Hybridization occurs when offspring are produced by interbreeding between genetically different populations

  21. In intermediate or transitional habitats, hybrid populations may be more fit than either parental population

  22. Hybrid Zones • Hybrid fitness Hybrid zone Outcome • < parents narrow, short lived reinforcement • = parents wide, long lived coalescence > parents depends stable zone or speciation

More Related