When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Evolution | Definition, History, Types, & Examples | Britannica

    www.britannica.com/science/evolution-scientific-theory

    Evolution, theory in biology postulating that the various types of living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations.

  3. Biology - Evolution, Genetics, Species | Britannica

    www.britannica.com/science/biology/Evolution

    Evolution itself is a biological phenomenon common to all living things, even though it has led to their differences. Evidence to support the theory of evolution has come primarily from the fossil record , from comparative studies of structure and function, from studies of embryological development , and from studies of DNA and RNA (ribonucleic ...

  4. Coevolution | Definition, Examples, & Facts | Britannica

    www.britannica.com/science/coevolution

    Coevolution, the process of reciprocal evolutionary change that occurs between pairs of species or among groups of species as they interact with one another. Each species in the interaction applies selection pressure on the others.

  5. Adaptation | Definition, Examples, & Facts | Britannica

    www.britannica.com/science/adaptation-biology-and-physiology

    adaptation, in biology, the process by which a species becomes fitted to its environment; it is the result of natural selection’s acting upon heritable variation over several generations.

  6. Natural selection | Definition & Processes | Britannica

    www.britannica.com/science/natural-selection

    For full treatment, see evolution: The concept of natural selection. In natural selection, those variations in the genotype (the entire complex of genes inherited from both parents) that increase an organism’s chances of survival and procreation are preserved and multiplied from generation to generation at the expense of less advantageous ...

  7. Convergent and parallel evolution - Encyclopedia Britannica

    www.britannica.com/science/evolution-scientific-theory/Convergent-and-parallel...

    Evolution - Convergent, Parallel, Adaptation: A distinction has to be made between resemblances due to propinquity of descent and those due only to similarity of function.

  8. Biology - Evolution, Natural Selection, Adaptation | Britannica

    www.britannica.com/science/biology/The-theory-of-evolution

    A complete theory of evolution was not announced, however, until the publication in 1859 of Charles Darwin’s On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. In his book Darwin stated that all living creatures multiply so rapidly that if left unchecked they would soon ...

  9. Evolution - Natural Selection, Adaptation, Genetics | Britannica

    www.britannica.com/science/evolution-scientific-theory/The-science-of-evolution

    Biological evolution is the process of change and diversification of living things over time, and it affects all aspects of their lives—morphology (form and structure), physiology, behaviour, and ecology. Underlying these changes are changes in the hereditary materials.

  10. Analogy | Comparative, Morphology & Genetics | Britannica

    www.britannica.com/science/analogy-evolution

    Analogy is one aspect of evolutionary biology and is distinct from homology (q.v.), the similarity of structures as a result of similar embryonic origin and development, considered strong evidence of common descent.

  11. Variation | Definition, Examples, & Facts | Britannica

    www.britannica.com/science/variation-biology

    Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).