Many of the plants in a grassland environment are specifically adapted to that habitat. The natural selection that led to this a
daptation was a result of all the following EXCEPT
populations of plants naturally exhibit variation
plants produce more offspring than can survive.
the available resources do not support all the plants,
related plant species share some genetic material.
Answer: hybridisation between related species is unlikely to contribute to adaptive speciation.
Explanation: any population has natural genetic variation. The available resources are insufficient for all plants (and conversely, not all offspring survive). Natural selection favours variations better suited to the conditions.
Although hybridisation is more common in plants than animals, and can lead to speciation, adaptive radiation from an ancestral species is the general response to environmental change, such as from rainforest to savanna. There is low probability of selective advantage from hybridisation of two ancestral species adapted to niches within the original habitat when the conditions in those niches changes significantly.
Genetic drift is changes in allele frequencies of a gene pool due to chance or random events. This can occur in large or small populations. Genetic drift causes gene pools of two isolated populations to become dissimilar as some alleles are lost and other are fixed.
