- Change in allele frequency at species or below species level is termed as
(1) Microevolution (2) Macroevolution
(3) Mega evolution (4) Silent evolutionWhat Is Microevolution?
Microevolution refers to the small-scale changes in the genetic makeup of a population, specifically changes in allele frequencies, that occur over relatively short periods of time. These changes happen within a species or even within a single population, rather than at higher taxonomic levels. Microevolution is driven by several key mechanisms:
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Mutation: Random changes in DNA that introduce new genetic variants.
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Genetic Drift: Random fluctuations in allele frequencies, especially in small populations.
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Gene Flow: Movement of genes between populations through migration.
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Natural Selection: Differential survival and reproduction of individuals based on their genetic traits.
Microevolution vs. Macroevolution
It’s important to distinguish microevolution from macroevolution:
Aspect Microevolution Macroevolution Scale Within species or populations Above species level (new species, genera, etc.) Time Frame Short-term (observable within generations) Long-term (millions of years) Mechanisms Mutation, drift, selection, gene flow Speciation, extinction, adaptive radiation Example Antibiotic resistance in bacteria, color changes in moths Evolution of birds from dinosaurs Microevolution is the foundation for macroevolution. Over long periods, the accumulation of microevolutionary changes can lead to the emergence of new species, a process known as speciation.
Why Is Microevolution Essential?
Microevolution explains how populations adapt to their environments, how resistance to drugs develops in pathogens, and how genetic diversity is maintained within species. It is observable over short time frames, making it a powerful concept for studying evolution in real time.
Examples of Microevolution
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Antibiotic Resistance: Bacterial populations evolve resistance to antibiotics through changes in allele frequency caused by mutation and selection.
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Peppered Moth: Changes in the frequency of light and dark colored moths in response to industrial pollution.
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Finch Beak Size: Variation in beak size among Galápagos finches due to natural selection during droughts.
Conclusion
Microevolution is the correct term for changes in allele frequency at the species or below species level. It is the process that underlies adaptation, genetic diversity, and the first steps toward the formation of new species. By understanding microevolution, we gain insight into how populations change and evolve over time, providing the foundation for the broader patterns of life’s diversity.
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