Allopatric Speciation and Habitat Adaptation – Lab Report Example
Purpose The purpose of this study is to determine if allopatric speciation i.e. divergence of species occurs because of geographic isolation Introduction
Allopatric speciation is the result of geographical isolation of species due to physical barriers and each separated population adopting specific physical features to suit their new habitat. A good example is the Caribbean Anolis lizards that have varied limb size and shape depending on whether they live on the ground or on trees. (Ref. Losos Laboratory, Department of Organismic and Evolutionary Biology, Harvard University).
However there are also cases where two physically isolated populations have not changed morphologically but do not interbreed. Snapping shrimps on either side of the Isthmus that links the North and South American continents are physically similar but the opposite sexes attack, rather than mate when artificially paired. Ref. Nancy Knowlton, Smithsonian Tropical Research Institute, Panama
It is hypothesized that physical or geographical isolation does not result in allopatric speciation or the creation of distinct species, based on the study by Futuyama and Mayer.
Our experiment was on observing and comparing the diversity in African Buffalo species present in different parts of the African continent.
Results showed that their skin colour, body mass (weight) and size has changed to suit their habitat as given in this Table.
Cape buffalo (Syncerus caffer caffer)
South and East Africa
Well built with Black skin Weight ~900 kg
Forest buffalo (S. c. nanus)
Central and West Africa
Red skin, ~4 feet height, weight ~270 kg
Sudanese buffalo (S. c. brachyceros)
Dark colour, weight ~600 kg
Nile buffalo (S.c. aequinoctialis)
Lighter than Cape buffallo, smaller
Based on this study, we can conclude that geographical isolation results in speciation accompanied with change in phenotype to match the local requirement. Therefore, our original hypothesis that “physical or geographical isolation does not result in allopatric speciation” has been proved to be incorrect.
1. .Douglas J. Futuyma and Gregory C. Mayer Non-Allopatric Speciation in Animals Systematic Zoology Vol. 29, No. 3 (Sep., 1980), pp. 254-271 URL: http://www.jstor.org/stable/2412661
2. Losos Laboratory, Department of Organismic and Evolutionary Biology, Harvard University.
3. Nancy Knowlton, Smithsonian Tropical Research Institute, Panama http://www.teachersdomain.org/resource/tdc02.sci.life.evo.allopatric/