Define mesomers with an example?

In Chemistry:

• Metamers are a type of isomers. They have the same molecular formula but different alkyl groups on either side of a functional group.
• This type of isomerism is called metamerism.
• Example: Ethers like C₂H₅–O–C₃H₇ and CH₃–O–C₄H₉ show metamerism because they have the same formula but different alkyl groups attached to oxygen.

In Biology:

• Metamerism refers to the presence of a linear series of repeating body segments, where each segment (called somite or metamere) has similar basic structure but may perform specialized functions.
• Example:
  • True Metamerism → Seen in earthworms, where each segment repeats organs and tissues.
  • Pseudometamerism → Seen in tapeworms, where segments are mainly for reproduction and nutrient exchange.

Note: Segmentation and Metamerism are not the same.

• Metamerism originates from mesodermal tissue,
• while Segmentation is derived from the ectoderm.

Additional Information:

• Mesomers: These are organic compounds having two identical chiral carbons. Since their optical activities cancel each other, the net rotation of plane-polarized light = 0.
• Example: 2,4-pentanediol.