If all flowers in a type of plant were only capable of self-pollination, how would it affect the genetic diversity over several generations? Explain.

If all flowers of a plant were only capable of self-pollination, genetic diversity in that plant species would progressively decrease with each successive generation. In self-pollination, pollen from the anther of a flower is transferred to the stigma of the same flower or another flower on the same plant. The gametes involved, therefore, originate from the same individual and carry the same pool of genetic information. No new genetic material from another individual is introduced.

Over several generations of exclusive self-pollination, the offspring would become increasingly alike. The variation present in the population would reduce continuously because there is no mechanism to generate new combinations of traits. Sexual reproduction in plants normally creates genetic diversity through cross-pollination, meiosis, and the random mixing of chromosomes from two different parent plants. Without cross-pollination, this source of variation is eliminated. Therefore, continuous self-pollination over several generations reduces genetic diversity and increases the vulnerability of the species.