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Home > Science > What is the Difference Between Homologous Structures and Vestigial Structures?

Guilherme Mazui

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What is the Difference Between Homologous Structures and Vestigial Structures?

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Homologous structures and vestigial structures are two types of anatomical structures that provide evidence of evolution and common ancestry. Here are the main differences between them:

Homologous Structures:

  • Anatomically similar structures present in different organisms.
  • Indicate a common function and suggest common ancestry.
  • Provide evidence for divergent evolution.
  • Examples include the limbs of mammals, which share a common ancestry and function.

Vestigial Structures:

  • Inherited structures that are no longer useful to an organism.
  • Sizes have become reduced with time since they have no function.
  • Provide evidence for a common ancestry but suggest that the structures have lost their original function.
  • Examples include the wings of an ostrich or the pelvic bones of a whale.

In summary, homologous structures are similar structures present in different organisms that share a common ancestry and function, while vestigial structures are inherited structures that are no longer useful to an organism and have lost their original function.

On this page
  • What is the Difference Between Homologous Structures and Vestigial Structures?
  • Comparative Table: Homologous Structures vs Vestigial Structures

    • Comparative Table: Homologous Structures vs Vestigial Structures

    Here is a table comparing homologous structures and vestigial structures:

    Feature Homologous Structures Vestigial Structures
    Definition Structurally similar structures present in different organisms, indicating a common ancestry. Anatomical structures that are not useful to an organism, inherited from ancestors but have become reduced in size and function over time.
    Purpose Provide evidence for divergent evolution and indicate evolutionary relationships between organisms. Provide evidence of common ancestry and can help trace the evolutionary origin of the species.
    Examples Limbs of birds, crocodiles, bats, whales, and humans. Human tail bone, whale pelvis, and dewclaws in pigs and cattle.
    Evolutionary Relationship Homologous structures are derived from a common ancestor, indicating that the organisms sharing them are evolutionarily related. Vestigial structures are inherited from ancestors and are homologous to fully functioning structures in related lineages, providing evidence of common ancestry.
    Functionality Homologous structures are usually functional and serve a purpose in the organism. Vestigial structures are nonfunctional or have a greatly reduced function compared to their ancestral form.
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.