Which statement about evolution is true?
A Evolution occurs in individual organisms.
B Evolution involves a change in inherited traits.
C Evolution can occur within a single generation.
The Correct Answer and Explanation is :
The correct answer is:
B. Evolution involves a change in inherited traits.
Explanation:
Evolution is a gradual process that involves changes in the inherited characteristics of populations over generations. At its core, evolution is defined as the change in the frequency of alleles (gene variants) within a population over time. These changes occur because of factors like natural selection, genetic drift, mutation, and gene flow, all of which act on populations rather than individual organisms.
Why Evolution Doesn’t Occur in Individuals:
Individual organisms do not evolve in the context of genetic changes that lead to evolutionary adaptation. While an individual may undergo physiological changes or adapt behaviorally during its lifetime, these changes are not passed on genetically to offspring in a way that affects population-level evolution. Instead, evolution is a process that impacts a population over multiple generations as beneficial traits become more common within the group.
Generational Time and Evolution:
Evolution typically spans multiple generations, allowing enough time for genetic variations to spread throughout a population. Significant evolutionary changes, especially in larger organisms, require extended periods. For example, bacteria may evolve rapidly due to short generational times, whereas mammals typically require thousands or even millions of years for substantial evolutionary changes.
Heritability and Evolution:
The crux of evolution lies in the inheritance of traits that offer some reproductive advantage. Natural selection favors traits that enhance survival or reproduction, leading to a gradual shift in the population’s genetic makeup. Evolutionary changes are cumulative and can be observed through comparative studies of fossils, DNA, and anatomy across generations.
In summary, evolution is a population-level process involving inherited traits that change over multiple generations, not within individuals or single-generation timelines.