homology
Noun: 1. The quality of being similar or corresponding in position, value, structure, or function: This is the core meaning, referring to a fundamental correspondence or similarity between different things, often due to shared origin or a common underlying principle. It implies a deep, structural similarity rather than a superficial one. 2. (Biology) Correspondence in type of structure in two or more species, due to descent from a common ancestor: In biology, it specifically refers to anatomical structures in different species that share a similar underlying form and evolutionary origin, even if their functions differ (e.g., a human arm, a bat's wing, and a whale's flipper). 3. (Chemistry) The relation of compounds in a homologous series: In chemistry, it denotes the relationship between members of a series of organic compounds (a homologous series) that differ by a constant increment, such as a CH₂ group (e.g., methane, ethane, propane). 4. (Mathematics) A concept in algebraic topology where two cycles are considered equivalent if they differ by a boundary: In advanced mathematics, homology is a formal algebraic procedure for classifying topological spaces by identifying and counting holes of different dimensions.
- General/Philosophical Use:
- Linguists study the homology between grammatical structures in different languages.
- There is a clear homology between the organization of a corporation and that of a traditional army.
- Biological Use:
- The pentadactyl limb is a classic example of homology, showing the same bone structure in the limbs of mammals, birds, and reptiles.
- Scientists use genetic homology to trace evolutionary relationships between species.
- Chemical Use:
- Methanol and ethanol exhibit homology as consecutive members of the alcohol series.
- Mathematical Use:
- The homology groups of a torus are different from those of a sphere, reflecting their distinct shapes.
- Homologous (adjective): The adjectival form used to describe things that exhibit homology.
- The forelimbs of vertebrates are homologous structures.
- Homologous chromosomes (Biology): A pair of chromosomes, one from each parent, that are similar in length, gene position, and centromere location.
- Homologous recombination (Genetics): A type of genetic recombination where nucleotide sequences are exchanged between two similar or identical molecules of DNA.
- Homologous (adj.): Having the same relation, relative position, or structure.
- Homologate (v.): To approve or confirm officially, especially in technical contexts like motorsports (a different but related meaning derived from "to agree").
- Homologation (n.): The process of official approval or confirmation.
- Analogy (n.): A similarity in function or appearance between things that are otherwise unrelated in structure or origin (often contrasted with in biology).
- Correspondence
- Similarity (structural)
- Equivalence
- Congruence
- Parallelism
- Heterology
- Analogy (in the specific biological sense of superficial similarity without common descent)
- Disparity
- Dissimilarity
- Homologous series (Chemistry): A series of organic compounds with the same functional group, where successive members differ by a CH₂ unit.
- Sequence homology (Biology/Genetics): The similarity of DNA, RNA, or protein sequences, indicating a common evolutionary origin.
- Structural homology (Biology): Similarity in the three-dimensional structure of proteins or other macromolecules.
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the quality of being similar or corresponding in position or value or structure or function
