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Types of developmental change

Developmental changes have likely been involved in important morphological changes — like the evolution of novel and complex structures.

Here are a few of the sorts of developmental changes that may have been important:

  • Module duplication and adaptation
    A module refers to a unit that can be duplicated and further adapted. For example, arthropods have various numbers of body segments. Segment duplication and loss is a developmental change that probably occurred many times in the evolution of this clade. The graphic below shows a hypothetical example of module duplication and adaptation.

Example of module duplication

  • Individualization
    This is the modification of a particular module, usually when there is selection for a specialized function.

    Scorpion pincers Spider mating appendages
    One set of scorpions' appendages has evolved into pincers whereas the same appendage in many spiders has evolved into colorful pompoms used in mating rituals.

Scorpion image courtesy of the California Academy of Sciences; Spider image courtesy of Michael Hedin, San Diego State University.

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More details
Read more about how development factored into the history of evolutionary thought.

Evo examples
Learn more about evolution and development in context: Why the eye?, a case study.

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