homology

American  

[huh-mol-uh-jee, hoh-] / həˈmɒl ə dʒi, hoʊ- /

noun

plural

homologies

1. the state of being homologous; homologous relation or correspondence.

2. Biology.

   1. a fundamental similarity based on common descent.

   2. a structural similarity of two segments of one animal based on a common developmental origin.

3. Chemistry. the similarity of organic compounds of a series in which each member differs from its adjacent compounds by a fixed increment, as by CH 2 .

4. Mathematics. a classification of figures according to certain topological properties.

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homology British  

/ həʊˈmɒlədʒɪ /

noun

1. the condition of being homologous

2. chem the similarities in chemical behaviour shown by members of a homologous series

3. zoology the measurable likenesses between animals, as used in grouping them according to the theory of cladistics

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homology Scientific  

/ hə-mŏl′ə-jē /

1. A homologous relationship or correspondence.

2. The relation of the chemical elements of a periodic family or group.

3. The relation of the organic compounds forming a homologous series.

4. A topological classification of configurations into distinct types that imposes an algebraic structure or hierarchy on families of geometric figures.

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Etymology

Origin of homology

1650–60; < Greek homología agreement, equivalent to homólog ( os ) homologous + -ia -y ³

Explanation

A good example of homology is the wing of a bird and the flipper of a whale, which have the same evolutionary origin. Consequently, they're in a similar place on the body and have some similar characteristics. Homology exists between any distinct things that are the same in some important way. The word comes from Greek homologia, meaning "agreement"; the combining form homo- means “same." In biology, homology exists between parts or structures that are similar in some way, including having the same evolutionary origin. This is different from analogy, which is a similarity that doesn't have a common evolutionary origin — such as the analogy between a bird's wing and a mosquito's: Both are used for flying, but they developed by independent paths.

Example Sentences

Homology resulting from common ancestors is seen at the molecular level too.

From Textbooks • Jan. 1, 2018

It's a ravishing tour, from the spangled glory of globular star cluster M13, imaged by the Hubble Space Telescope, to Martin Krzywinski's bold 2007 radial genomics diagram Human–Dog Homology.

From Nature • May 9, 2017

Homology, as this kind of relatedness is called, is among “the first and in many ways the best evidence for evolution,” says Josh Rosenau of the National Center for Science Education.

From Slate • Oct. 18, 2013

Homology is still determined by position, by connections, in the embryo as in the adult.

From Form and Function A Contribution to the History of Animal Morphology by E. S. (Edward Stuart) Russell

Homology of names should, in our opinion, always accompany homology of regions.

From Artistic Anatomy of Animals by Cuyer, ?douard

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