What is evolution?

Satunnainen

Evolution is a biological process in which species change over time. This change occurs when hereditary characteristics are passed from one generation to another. The basic mechanisms of evolution include natural selection, mutations, gene flow and genetic drift. Evolution explains how diversity and adaptation have arisen in the history of life on Earth.

Basic mechanisms of evolution

Evolution is based on several key mechanisms that affect the development and adaptation of species to their environment. These mechanisms include:

  • Natural selection: Natural selection is a process in which the environment favors individuals with certain characteristics that survive and reproduce better than others. This leads to the generalization of these characteristics in the population.
  • Mutations: Mutations are random changes in DNA that can lead to new characteristics. Although most mutations are neutral or harmful, some can be beneficial and contribute to the survival and reproduction of the individual.
  • Gene flow: Gene flow occurs when individuals move from one population to another and bring new genes with them. This can increase genetic diversity and affect population evolution.
  • Genetic drift: Genetic drift is a random process in which the frequency of alleles (gene forms) in a population changes over generations. This can lead to the generalization or disappearance of certain characteristics without the influence of natural selection.

Evidence of evolution

The theory of evolution is supported by many evidences from different scientific fields. This evidence includes, but is not limited to:

  1. Fossils: Fossils provide direct evidence of past organisms and their evolution. Fossil finds show how certain species have changed over time and how new species have arisen.
  2. Comparative anatomy: Comparing the structures of different species reveals similarities that point to a common origin. For example, the bone structures of the forelimbs of mammals are very similar, although their purposes are different.
  3. Genetic research: Comparing DNA sequences between different species shows how closely they are related to each other. Genetic similarities support the concept of common origin and evolution.
  4. Biogeography: The distribution of organisms on Earth gives clues about their evolution. For example, species living on isolated islands have often developed distinctive characteristics because they have been isolated from other populations.

The meaning of evolution

Evolution is a central concept in biology, and it helps to understand the diversity and adaptation of life. The theory of evolution offers an explanation for why certain characteristics have become common or lost in populations and how new species arise. It also helps predict how organisms can adapt to changing environmental conditions.

You can read more about evolution from, for example, the following sources:
Nature – Evolution 101 and Khan Academy – What is evolution?.

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