Populations
- A population can be defined as:
A group of organisms of the same species living in an area at one time
- Members of a population interact with each other and can breed together
- A population can be isolated from other populations of the same species due to living in a different area
- This isolation means that members of separate populations cannot breed together and gene exchange cannot take place between them
CC BY 2.0, via Wikimedia Commons
Gannets are sea birds. Populations gather on sea cliffs to breed during nesting season.
Examiner Tip
The IB specification uses the phrase 'reproductive isolation' here to describe two populations of the same species that are separate from each other, i.e. isolated, and that are not interbreeding. While this does make sense in this context, it is worth noting that the term reproductive isolation is more frequently used among biologists to describe the point in the speciation process at which two populations have diverged to become two different species.
