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Luonnonvalinta, or natural selection, is a fundamental mechanism of evolution described by Charles Darwin. It refers to the process whereby individuals with certain heritable traits are more likely to survive and reproduce in their environment, thereby passing those advantageous traits to subsequent generations. Over time, natural selection can lead to adaptations within a population, enhancing the species’ ability to thrive in specific ecological niches.

The process operates through several key factors: variation, differential survival, and reproduction. Genetic variation exists within populations due to mutations, genetic recombination, and gene flow. Some variations confer advantages or disadvantages depending on environmental conditions. Individuals with beneficial traits are more likely to survive predation, competition, and harsh environments, increasing their reproductive success. Conversely, those with less advantageous traits are less likely to reproduce, leading to a gradual shift in the population’s genetic makeup.

Natural selection can take different forms, including stabilizing selection (which favors the average traits), directional selection (which favors traits at one extreme), and disruptive selection (which favors extreme traits at both ends). It plays a vital role in shaping biodiversity, enabling species to adapt to changing environments over generations.

Natural selection is widely supported by evidence from various fields, including genetics, paleontology, and ecology. It underpins the theory of evolution and explains the diversity of life on Earth. While environmental factors drive natural selection, it is important to note that the process is gradual and does not have a predetermined direction, being guided instead by the complex interactions between organisms and their environment.