Life Sciences Term 3

Speciation

• Population:  individuals of the same species living in the same area that can randomly interbreed
  
• Species: organisms that have the same characteristics, capable of random interbreeding and producing fertile offspring
  
• Speciation: is the evolutionary process by which populations evolve to become distinct species
  
• Geographical isolation and reproductive isolation mechanisms isolate the gene pool of a species resulting with formation of new species

Speciation through geographic isolation:

• If a population of a single species becomes separated by a geographical barrier (sea, river, mountain, lake) then the population splits into two
  
• There is now no gene flow between the two populations
• Since each population may be exposed to different environmental conditions/the selection pressure may be different
• Natural selection occurs independently in each of the two populations such that the individuals of the two populations become very different from each other genotypically and phenotypically
  
• Even if the two populations were to mix again they will not be able to interbreed
  
• The two populations are now different species