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 in a type of plant were only capable of self-pollination, it would significantly decrease the genetic diversity over several generations. Since self-pollination involves the transfer of pollen within the same flower or plant, there is no mixing of genetic material from different individuals as occurs in cross-pollination.
Normally, sexual reproduction creates variation among individuals. Without the introduction of new genetic material from another plant, the offspring produced over generations will be genetically very similar to the parent.
This lack of variation is harmful because variation helps individuals adapt better to changing environments. Reduced genetic diversity would make the plant species less capable of adapting and surviving environmental changes over time.
Explanation
The textbook context highlights that sexual reproduction creates variation among individuals, which is crucial for the survival of a species and adaptation to changing environments. Self-pollination involves the transfer of pollen within the same flower or plant, lacking the genetic mixing that occurs during cross-pollination (transfer between different plants). Therefore, if a plant relies solely on self-pollination, it misses out on the genetic recombination from different individuals, leading to reduced variation and a significant decrease in genetic diversity over several generations.