metamerism
- Noun:
- Biological segmentation: "metamerism" refers to the condition of being composed of a linear series of similar segments (metameres) along the body axis, as seen in annelids and arthropods.
- Chemical isomerism: In chemistry, "metamerism" is a type of structural isomerism where compounds have the same molecular formula but differ in the arrangement of alkyl groups on either side of a functional group (e.g., an ether or ester).
Biological context:
- The earthworm exhibits clear metamerism, with each body segment containing similar organs. (The worm's body is divided into repeated, similar sections.)
- Metamerism in arthropods allows for specialized appendages on different segments. (Segmentation enables adaptation of body parts for various functions.)
Chemical context:
- Metamerism is observed in ethers like diethyl ether and methyl propyl ether, which share the formula C₄H₁₀O but have different alkyl groups. (These isomers differ in how carbon chains are attached around the oxygen atom.)
- In organic chemistry, metamerism is less common than other forms of isomerism. (This type of structural variation is relatively rare.)
"homonomous metamerism": a type of metamerism where all body segments are similar to each other.
- In primitive annelids, homonomous metamerism is the norm. (All segments are nearly identical.)
"heteronomous metamerism": metamerism where segments are differentiated for different functions.
- The heteronomous metamerism of insects includes head, thorax, and abdomen. (Segments are specialized into distinct body regions.)
"metamerism in color perception": In color science, "metamerism" also describes the phenomenon where two colors appear identical under one light source but different under another.
- The two fabrics show metamerism; they match in daylight but clash under fluorescent light. (The colors are metamers—visually matched in one illumination but not another.)
Metameric (adj): relating to or exhibiting metamerism.
- The metameric structure of the annelid is clearly visible. (The segmented body plan is apparent.)
Metamere (n): a single body segment in a series of similar units.
- Each metamere contains a ganglion and a pair of nephridia. (Each segment has its own nerve and excretory organs.)
Metamer (n): in chemistry, one of a set of metamers; also used in color science for a color that matches another under a specific illuminant.
- The two samples are metamers under daylight. (They appear identical in daylight but may differ under other lights.)
- Segmentation: the division of an organism into repeated segments (biological context).
- Serial homology: the repetition of similar body parts along the axis (biological context).
- Structural isomerism: a broader term for isomers with different bonding arrangements (chemical context, though metamerism is a specific subtype).
"a case of metamerism": used in color science to describe a situation where two objects match under one light but not another.
- The paint samples are a classic case of metamerism. (They match in store lighting but not in sunlight.)
"metamerism in design": in fashion or interior design, refers to the challenge of matching materials that appear identical under only certain lighting.
- We avoided metamerism by testing all fabrics under multiple light sources. (We ensured consistent color appearance.)