Geographic modes of speciation in nature
Speciation is the evolutionary creation of new biological species. Genetic drift is assumed as a minor or major contributor to this process.
The four modes of speciation
1. Allopatric – a geographically isolated populations
2. Peripatric - a small population isolated at the edge of a larger population
3. Parapatric - a continuously distributed population
4. Sympatric - within the range of the ancestral population
Through animal husbandry or experiments the speciation process can be induced artificially. The genetic variation between species is the main concept of speciation.
Genetic difference must be there in two incipient species, and they are expressed occasionally. It may cause no mating between them or failure matings. Big genetic differences are not necessary. A minute change in the location or the process of mating could also make a difference. But definitely there must be some difference. This variation might evolve by genetic drift or selection. Gene flow reduction is the major part of speciation.
Reduced gene flow probably plays a critical role in speciation. The 4 geographic modes of speciation are divided according to the species separation and the decrease in gene flow.
Allopatric Speciation:
It is a speciation by geographic isolation. Some extrinsic restricts the organisms from regular mating and cause lineage to speciation. Allopatric speciation can even occur through minute pores in the barriers. The individual organisms can seep through it and mate with other individuals.
Peripatric Speciation:
It is a subdivision of allopatric speciation. Formed new species are separated as a new small group. These smaller groups are restricted from gene exchange with the original population. It is more or less like founder effect. Smaller populations face the bottle necks. Genetic drift is has a major role in this speciation.
Parapatric Speciation:
Two diverging populations are partially separated geographically. Individual organisms can contact with the habitats. It restricts their inter-breeding and constant variations occur and it is absolutely a source for natural selection.
Ecologists refer to parapatric and peripatric speciation in terms of the ecological niches which are available for successful new species.
Sympatric speciation:
Species like insects diverge while inhabiting the same place and become dependent on various host plants in the same area.
Artificial Speciation
Domesticated animal husbandry plays an important role in the creation of new species.
Hybrid Speciation
Distinct phenotype occurrence is possible if different species gets hybridized.
Want to know more about Artificial and Hybrid speciation? Click here to schedule live online session with e Tutor!
About eAge Tutoring:
eAgeTutor.com is the premium online tutoring provider. Using materials developed by highly qualified educators and leading content developers, a team of top-notch software experts, and a group of passionate educators, eAgeTutor works to ensure the success and satisfaction of all of its students.
Contact us today to learn more about our tutoring programs and discuss how we can help make the dreams of the student in your life come true!
Reference Links:
- http://evolution.berkeley.edu/evosite/evo101/VSpeciation.shtml
- http://en.wikipedia.org/wiki/Speciation
- http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Speciation.html
- http://www.globalchange.umich.edu/globalchange1/current/lectures/speciation/speciation.html
- http://www.youtube.com/watch?v=v9i2WYS60L4&NR=1