Knowledge and Skills Statement
Variation within a population is never a disadvantage to the population, though sometimes a variation may be both advantageous to the population and disadvantageous to an individual. For example, in humans, the gene for sickle cell anemia confers resistance to malaria in people who have one copy, but people with two copies of the gene have sickle cell disease. For this reason, variations that are disadvantageous to an individual may remain in the population; the disadvantageous variation confers an advantage to hybrid organisms.
Research
Loiselle, Bette A., and John G. Blake. “Population Variation in a Tropical Bird Community.” BioScience 42, no. 11(1992): 838–845.https://doi.org/10.2307/1312083.
Summary: This scientific article explains the population variations in a tropical bird community. The flexibility of birds to move within a habitat allow for many species to thrive; however, habitat conservation is important to maintain a healthy balance.