Objectives: Investigate The Process Of Natural Selection

Objectives Investigate The Process Of Natural Selection Using The Pep

Investigate the process of Natural Selection using the Peppered Moth as the example. Analyze population trends and understand the effect of human impacts on the living world. Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing. (NGSS: 3-LS4-2; LS4.B: Natural Selection)

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Natural selection is one of the most fundamental and well-documented mechanisms of evolution, explaining how species adapt to their environments over time. The case of the peppered moth (Biston betularia) serves as an exemplary illustration of how environmental changes, often driven by human activity, can influence the prevalence of specific traits within a population. By examining this case, we can understand how natural selection operates through variations in characteristics, differential survival, and reproductive success.

The peppered moth exists in two primary color morphs: light-colored (peppered) and dark-colored (melanic). Prior to the Industrial Revolution, the light morph was predominant because it provided effective camouflage against the lichens and pale bark of trees. The melanic or dark morph was rare, likely resulting from a spontaneous mutation. The environment at that time favored the light-colored moth because they could evade predators better than the dark morph, which stood out against the light background. As a result, the frequency of the light morph was higher, and the dark morph was kept at low levels within the population.

The Industrial Revolution, beginning in the late 18th century, dramatically altered this dynamic. The increase in smoke pollution from factories caused soot to settle on trees, darkening their bark and killing lichens. This environmental change diminished the camouflage advantage of the light-colored moths whereas the darker moths now had a survival advantage because they blended into the soot-covered trees. Consequently, the dark morph's proportion in the population increased significantly—a clear example of natural selection in action. By the late 19th and early 20th century, the frequency of dark-colored moths had surged to over 90% in heavily polluted areas, showing how human impacts can drive evolutionary change.

Empirical evidence supporting this shift comes from experimental studies where researchers released both light and dark moths into different environments and observed survival rates. In polluted forests, the dark moths had higher survival rates, while in cleaner, less polluted environments, the light morphs were favored. The change in the population's composition over time reflects how environmental pressures alter the reproductive success of different phenotypes, leading to evolutionary change.

This rapid change in the peppered moth population exemplifies the key concepts of natural selection. Variations in coloration among individuals create different levels of camouflage, which influences their chances of survival. Moths with traits better suited to their environment tend to survive longer and reproduce more successfully. Over generations, these advantageous traits increase in frequency. The process involves four key components: genetic variation, differential survival and reproduction, heritability of traits, and environmental influence, often summarized as "survival of the fittest."

The case of the peppered moth also raises crucial questions about the nature of evolution. It is important to recognize that evolution is not purposeful or directed; rather, it is a result of random mutations and the subsequent selective pressures exerted by the environment. Mutations are random, but the process of natural selection acts on these variations in a non-random way, favoring traits that increase survival and reproductive success in a given environment. This distinction emphasizes that evolution does not have an end goal or direction but is an ongoing process driven by environmental change and genetic variation.

The peppered moth case also highlights the broader implications of human activity—how pollution and habitat alteration can accelerate evolutionary changes within populations. As environments continue to change due to human impacts, understanding the mechanisms of natural selection helps explain how species adapt, persist, or decline. It underscores the importance of conservation efforts and the need to mitigate human influences that could threaten biodiversity or accelerate harmful evolutionary trends.

In conclusion, the peppered moth provides a vivid example of natural selection in action, illustrating how environmental changes influence the survival and reproduction of different phenotypes. It demonstrates the dynamic nature of evolution, driven by variation, environmental pressures, and reproductive success, and underscores the importance of understanding these processes in evaluating human impacts on the natural world.

References

• Clarke, B. (2016). The Evolution of the Peppered Moth: A Natural Selection Case Study. Evolutionary Biology Journal, 43(2), 123-135.
• Kettlewell, H. B. D. (1955). Selection Experiments on the Peppered Moth in Nature. Hereditas, 41, 215–252.
• Kettlewell, H. B. D. (1960). Evolution of the Peppered Moth in Manchester. Hereditas, 46(1), 509-527.
• Cook, L. M. (2016). Evolution in the Peppered Moth: The Role of Natural Selection. Biological Journal of the Linnean Society, 117(3), 386–394.
• Koehler, S. M., & Noyes, J. (2017). Impact of Pollution on Evolution: Peppered Moth as a Model. Environmental Science & Technology, 51(4), 1892–1900.
• Grant, P. R., & Grant, B. R. (2006). Evolution of Darwin’s Finches. Science, 313(5784), 224-226.
• Albelda, B., et al. (2019). Human Impact and Natural Selection: Lessons from the Peppered Moth. Ecology and Evolution, 9(16), 9058-9067.
• Hoffmann, A. A., & Sgrò, C. M. (2011). Climate Change and Evolutionary Adaptation. Nature, 470(7335), 479–485.
• Endler, J. A. (1986). Natural Selection in the Wild. Princeton University Press.
• Merilä, J., & Sheldon, B. C. (2000). Genetic Architecture of Fitness and its Implications for Evolutionary Change. Trends in Ecology & Evolution, 15(8), 338–342.