Evolution (AQA A Level Biology)

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Evolution

  • The allele frequencies (within the gene pool) of a population can change over time due to processes such as natural selection
  • When the allele frequencies of a population change sufficiently over time, the characteristics of the species will also change
  • These changes can become so great that a new species forms
  • This process is known as evolution
  • Evolution can be defined as:

The formation of new species from pre-existing species over time, as a result of changes to gene pools and allele frequencies from generation to generation

  • The formation of new species via the process of evolution has resulted in a great diversity of species on planet Earth
    • Theoretically, at the origin of life on Earth, there would have been just one single species, to begin with
    • This species evolved into separate species (i.e. new species)
    • These species would then have divided again, each forming new species once again
    • Over millions of years, evolution has led to countless numbers of these speciation events, resulting in the millions of species now present on Earth

Diversity of species, downloadable AS & A Level Biology revision notes

Evolutionary change over a long period of time has resulted in a great diversity of species

  • The evolution of a new species can take a very long time and many generations
  • For organisms with a short generation time (such as bacteria), evolution can be observed far more quickly

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.