A species of bird has slight variations in its beak size and shape. Some individuals with bigger beaks are better at cracking seeds. Some individuals with narrower beaks are better at hunting for bugs. An invasion species is introduced that hunts all of the bug population, wiping out that food source for the birds, so all they are left with is seeds. Explain how genetic variation from sexual reproduction can save this species from extinction.
Genetic variation resulting from sexual reproduction can play a crucial role in saving the bird species from extinction in this scenario. When two individuals reproduce sexually, their genes combine to form unique offspring with a combination of traits from both parents. This diversity in offspring ensures that there is a range of beak sizes and shapes within the population, even if the initial population was predominantly made up of individuals with either bigger or narrower beaks.
Now, in this situation where the bug population, which was a food source for individuals with narrower beaks, has been wiped out, the individuals with bigger beaks are at an advantage because they are better suited for cracking seeds.
However, due to the presence of genetic variation, there might still be some individuals within the population who possess narrower beaks. These individuals may have acquired the genetic traits for narrower beaks from their parents, which might not have expressed themselves in the previous generation because the bug population was abundant, and bigger beaks were advantageous.
With the lack of bug prey, these individuals with narrower beaks suddenly have an advantage over those with bigger beaks because they can continue to feed on smaller seeds or alternative food sources. This advantage increases their chances of survival and reproduction, allowing them to pass on their narrow beak traits to the next generation.
Over time, this genetic variation and adaptation to the new food source can lead to the evolution of a subpopulation with narrower beaks. As this population continues to reproduce, natural selection favors the individuals with narrower beaks, increasing their frequency within the population.
Hence, the genetic variation provided by sexual reproduction allows the bird species to adapt to changing conditions. It ensures that there is a pool of diverse individuals with different traits, capable of surviving and passing on advantageous traits to their offspring. In this way, sexual reproduction helps the species overcome detrimental changes in their environment, such as the invasion of a predator and the consequent disruption of their food sources.