Speciation
Biology: IB Diploma Higher Level, topic 4.3.7
Overview of Speciation
Speciation is where two new species arise from a single species. This happens when two populations are prevented from interbreeding.
Reproductive isolation
- A species is defined as a group of organisms that can successfully interbreed to produce fertile offspring.
- If two populations are prevented from interbreeding, differences begin to accumulate in the two gene pools.
- Gene flow is the movement of alleles between a population. When two populations are reproductively isolated, the gene flow of the populations is restricted.
- The two populations are said to be reproductively isolated.
Accumulation of differences
- If the gene pools are reproductively isolated for an extended period of time, they will eventually accumulate enough genetic differences that the two populations can no longer interbreed.
- If individuals from the two populations can no longer interbreed to produce fertile offspring, the two populations are considered separate species.
Speciation
- Speciation is when two (or more) populations have been reproductively isolated to produce two (or more) separate species.
- This is how the thousands of species that exist today have been produced.
Test yourself on Speciation
Which of these is necessary for speciation to take place?