GCSE Biology (AQA)

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Speciation

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Inheritance, Variation and Evolution The Development of Understanding of Gentics and Evolution

Speciation

4:02 Theories of Evolution and Speciation
Spec 4.6.3.2
Previous Lamarck's Theory Next Gregor Mendel
  • Speciation is the gradual formation of a new species over hundreds of thousands to millions of years through evolution.
  • Alfred Russell Wallace first proposed the idea of speciation during his travels in Asia.
  • Wallace spent four years in the Amazon rainforest and eight years in the East Indies (now Singapore, Malaysia, and Indonesia), observing animal evolution.
  • For exams, it's important to recognize Wallace as the first to propose speciation but not necessary to detail how evidence has shaped current understanding.
  • Speciation occurs when individuals of a species become isolated due to environmental changes like mountain ranges, ice melting, or rivers forming.
  • Isolated groups breed separately, increasing genetic variation through mutations.
  • Natural selection favors alleles that enhance survival and reproduction in new environmental conditions.
  • Example: Bird populations separated by a mountain range evolved different beak shapes (blunt for nuts and seeds, pointed for insects) due to available food sources.
  • Over many generations, these adaptations can lead to significant differences, eventually preventing interbreeding and leading to the formation of new species.
  • This process exemplifies how speciation can lead to diversity in traits like beak shapes adapted to specific diets.

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