Biogeography Introduction to Evolution and Scientific Inquiry Dr. - - PowerPoint PPT Presentation

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Biogeography Introduction to Evolution and Scientific Inquiry Dr. - - PowerPoint PPT Presentation

Jan 20, 2023 131 likes •340 views

Biogeography Introduction to Evolution and Scientific Inquiry Dr. Stephanie J. Spielman; spielman@rowan.edu Biogeography Biogeography is the study of the geographic distribution of species and the processes which give rise to these

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Biogeography

Introduction to Evolution and Scientific Inquiry

  • Dr. Stephanie J. Spielman; spielman@rowan.edu
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Biogeography

  • Biogeography is the study of the geographic distribution of species and the

processes which give rise to these distributions

  • E.g., this is..not right.

studies the patterns of geographic distribution of organisms and the causes for these patterns.

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Alfred Russell Wallace: "Father" of biogeography

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Wallace's Line

Observed distinct fauna (animal) distributions on different sides of this line. The earliest "biogeographic border"

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A few biogeographical patterns

Biodiversity hotspots in the tropics Islands tend to have fewer species

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How do species get to live where they do?

  • Vicariance: Changes in geography drive changes in species distributions

○ The Earth moves you

  • Dispersal: A species extends its geographic range into a new area where it did

not previously live

○ You move somewhere else

  • One of two things will happen when a species ends up in a new geographic

region.

○ It adapts to the new environment and survives ○ It fails to adapt to the new environment and goes extinct ○ Hence, we see many adaptations!

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Convergent evolution in similar habitats is a signal of adaptation

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Convergence often signals adaptation

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Species history from phylogenies

Each color is a distinct geographic area

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Speciation, vicariance, and phylogenies

Lines indicate new geographic barriers, and letters (x,y,z) represent species

A geographic region Vicariance event leads to speciation Another vicariance

  • event. How about

speciation?

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Hawaiian Drosophila species relationships match

  • rder of island origin
  • Means that vicariance is a major determinant
  • f species distributions
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Geologic changes over time by continental drift

https://www.youtube.com/watch?v=UwWWuttntio

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A case study: Ratite Bird Biogeography

Ratites are flightless birds. How do they have this geographical distribution?

A flying relative**

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One hypothesis: distribution by vicariance

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If vicariance, the phylogeny would EXACTLY MATCH the geography changes

Ostrich (Africa) Elephant Bird (Africa, extinct) Kiwi (New Zealand) Moa (New Zealand, extinct) Emu + cassowary (Australia) Rheas (South America) Tinamous outgroup (South America)

10.1126/science.1251981

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The phylogeny made from DNA is very different - so dispersal contributed to speciation

Ostrich (Africa) Elephant Bird (Africa, extinct) Kiwi (New Zealand) Moa (New Zealand, extinct) Emu + cassowary (Australia) Rheas (South America) Tinamous outgroup (South America) Tinamous (South America) Moa (New Zealand, extinct) Elephant Bird (Africa, extinct) Kiwi (New Zealand) Emu + Cassowary (Australia) Rheas (South America) Ostrich (Africa)

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Fossil data reveals a Northern hemisphere (Laurasia)

  • rigin

http://dx.doi.org/10.1016/j.cub.2016.12.023

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Another overall view

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Another example: snapping shrimp