Directional Selection and Disruptive Selection

Directional Selection and Disruptive Selection

Both directional selection and disruptive selection are natural selection mechanism types that influence allele frequency. They increase the favored phenotype’s allele frequency within the population and are directly responsible for a specific phenotype’s selection over successive generations. The discrepancy between the two is that, while extreme values are favored over intermediate values for a trait in a disruptive selection, a phenotype most fitted to the surrounding is favored in directional selection (Lakna, 2019). Consequently, directional selection only selects a single phenotype, while disruptive selection selects more than one phenotype. An example of directional selection is the dark-colored moth selection over the light-colored moth after evolution. On the other hand, sneaking males and alpha males selection in a lobster population over intermediate males is an example of a disruptive selection.

Microorganism’s ability to withstand the effects of an antibiotic is what is termed antibiotic resistance. According to Galimov & Gems (2021), this resistance evolves naturally through random mutation through natural selection but can also be engineered by applying evolutionary stress on a population. As bacteria get killed, others survive and produce offspring that can survive overcome the antibiotic. The process happens through natural selection and leads to an increase in the number of resistant Bactria.

In Biology, life is defined as any system capable of performing tasks such as breathing, eating, reproducing, metabolizing, responding to external stimuli, growing, excreting, and moving (Tetz & Tetz, 2020). Biologists believe that life originates in a natural process whereby life arises from non-living matters like organic compounds. Despite the diversity of eukaryotic cells in function, form, and shape, they share standard features such as plasma cell membrane, cytoskeleton, and internal membrane-bound organelles. The three primary lines of evidence include the fact that they have their cell membranes, have their own circular DNA genome, and pinch in half to multiply.


Galimov, E. R., & Gems, D. (2021). Death happy: adaptive ageing and its evolution by kin selection in organisms with colonial ecology. Philosophical Transactions of the Royal Society B376(1823), 20190730.

Lakna. (2019). What is the Difference Between Directional and Disruptive Selection – Pediaa.Com. Pediaa.Com.,a%20trait%20over%20intermediate%20values.

Tetz, V., & Tetz, G. (2020). A new biological definition of life. Biomolecular Concepts11(1), 1-6.

Scroll to Top