A Bird’s Wings Are Homologous to

A Bird’s Wings Are Homologous to

20.2A: Distinguishing betwixt Similar Traits

  • Folio ID
  • Learning Objectives
    • Explain the difference betwixt homologous and analogous structures

    Ii Options for Similarities

    In general, organisms that share similar concrete features and genomes tend to be more closely related than those that do not. Such features that overlap both morphologically (in form) and genetically are referred to as homologous structures; they stalk from developmental similarities that are based on evolution. For instance, the bones in the wings of bats and birds have homologous structures.

    Figure \(\PageIndex{1}\): Homologous structures: Bat and bird wings are homologous structures, indicating that bats and birds share a common evolutionary past.

    Notice it is not simply a single bone, merely rather a grouping of several bones bundled in a similar fashion. The more complex the feature, the more probable that any overlap is due to a common evolutionary past. Imagine two people from dissimilar countries both inventing a car with all the same parts and in exactly the aforementioned arrangement without any previous or shared cognition. That outcome would be highly improbable. Withal, if 2 people both invented a hammer, it would exist reasonable to conclude that both could have the original idea without the help of the other. The aforementioned relationship between complexity and shared evolutionary history is true for homologous structures in organisms.

    Misleading Appearances

    Some organisms may be very closely related, even though a small-scale genetic change acquired a major morphological difference to make them await quite different. Similarly, unrelated organisms may be distantly related, but announced very similar. This ordinarily happens considering both organisms developed common adaptations that evolved within similar environmental conditions. When like characteristics occur because of environmental constraints and non due to a close evolutionary relationship, it is chosen an illustration or homoplasy. For example, insects use wings to fly similar bats and birds, but the wing structure and embryonic origin is completely different. These are called analogous structures.

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    Figure \(\PageIndex{1}\): Analogous structures: The (c) wing of a honeybee is similar in shape to a (b) bird fly and (a) bat wing, and information technology serves the same office. However, the honeybee wing is not composed of bones and has a distinctly-different structure and embryonic origin. These fly types (insect versus bat and bird) illustrate an illustration: like structures that practise non share an evolutionary history.

    Like traits tin can be either homologous or analogous. Homologous structures share a similar embryonic origin; analogous organs take a like function. For instance, the bones in the front flipper of a whale are homologous to the bones in the homo arm. These structures are not analogous. The wings of a butterfly and the wings of a bird are analogous, but not homologous. Some structures are both analogous and homologous: the wings of a bird and the wings of a bat are both homologous and analogous. Scientists must determine which type of similarity a feature exhibits to decipher the phylogeny of the organisms being studied.

    Molecular Comparisons

    With the advocacy of DNA technology, the area of molecular systematics, which describes the use of information on the molecular level including Dna assay, has blossomed. New computer programs not only ostend many earlier classified organisms, but also uncover previously-fabricated errors. As with physical characteristics, even the DNA sequence tin can exist catchy to read in some cases. For some situations, ii very closely-related organisms can appear unrelated if a mutation occurred that caused a shift in the genetic code. An insertion or deletion mutation would movement each nucleotide base over one identify, causing two similar codes to appear unrelated.

    Sometimes two segments of DNA lawmaking in distantly-related organisms randomly share a high percentage of bases in the same locations, causing these organisms to announced closely related when they are not. For both of these situations, computer technologies take been adult to help identify the bodily relationships. Ultimately, the coupled use of both morphologic and molecular information is more effective in determining phylogeny.

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    Key Points

    • Organisms may be very closely related, fifty-fifty though they look quite different, due to a minor genetic change that acquired a major morphological deviation.
    • Unrelated organisms may appear very similar because both organisms developed common adaptations that evolved within similar environmental conditions.
    • To make up one’s mind the phylogeny of an organism, scientists must determine whether a similarity is homologous or analogous.
    • The advancement of DNA technology, the area of molecular systematics, describes the use of information on the molecular level, including DNA assay.

    Cardinal Terms

    • analogous: when like similar concrete features occur in organisms because of ecology constraints and not due to a close evolutionary human relationship
    • homologous: when like physical features and genomes stalk from developmental similarities that are based on evolution
    • phylogeny: the evolutionary history of an organism
    • molecular systematics: molecular phylogenetics is the analysis of hereditary molecular differences, mainly in Dna sequences, to gain information on an organism’due south evolutionary relationships

    A Bird’s Wings Are Homologous to

    Source: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/20%3A_Phylogenies_and_the_History_of_Life/20.02%3A_Determining_Evolutionary_Relationships/20.2A%3A__Distinguishing_between_Similar_Traits