Panmixia

If there is no random sub-sampling of gametes involved in the fertilization cohort, panmixia has occurred.

In simple terms, panmixia (or panmicticism) is the ability of individuals in a population to interbreed without restrictions; individuals are able to move about freely within their habitat, possibly over a range of hundreds to thousands of miles, and thus breed with other members of the population.

However, outside population factors, like drought and limited food sources, can affect the way any species will mate.

[8] A panmictic population of Monostroma latissimum, a marine green algae, shows sympatric speciation in southwest Japanese islands.

[9] Dawson's burrowing bee, Amegilla dawsoni, may be forced to aggregate in common mating areas due to uneven resource distribution in its harsh desert environment.