How does natural selection favor individuals that are better adapted to their environment?
How does natural selection favor individuals that are better adapted to their environment?
Answered step-by-step
Natural selection is a fundamental mechanism of evolution that favors individuals better adapted to their environments. This process operates through several key principles:
1. Variation Among Individuals
Natural selection relies on the existence of variation within a population. Individuals possess different traits due to genetic differences, which can arise from mutations, gene flow, and sexual reproduction. This variation is crucial because it provides the raw material for selection; without it, there would be no traits for natural selection to act upon.
2. Differential Survival and Reproduction
Individuals with traits that confer advantages in their specific environments are more likely to survive and reproduce. This concept is often summarized by the phrase “survival of the fittest,” where “fitness” refers not just to survival but also to reproductive success. For example, a faster gazelle may escape predators more effectively than slower ones, allowing it to reproduce more successfully.
3. Heritability of Traits
For natural selection to lead to evolutionary change, the advantageous traits must be heritable—passed from parents to offspring. This means that the next generation will inherit these beneficial traits, increasing their chances of survival in similar environmental conditions. Over generations, these traits become more common within the population.
4. Adaptation to Environmental Pressures
Natural selection drives adaptation, which is the process through which populations become better suited to their environments over time. As environmental conditions change or as individuals migrate to new habitats, those with traits that enhance their survival in these contexts will thrive and reproduce more effectively. For instance, finches on the Galápagos Islands have evolved different beak shapes depending on the available food sources, demonstrating how natural selection shapes adaptations based on environmental pressures.
5. Long-Term Evolutionary Change
Through repeated cycles of variation, selection, and inheritance, populations can undergo significant changes over time. This process can lead not only to adaptations within a species but also to speciation—the emergence of new species as populations evolve in response to different selective pressures
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