Tympanum. (Eardrum). The membrane that separates the outer ear from the middle ear. It vibrates in response to sound waves and transmits these vibrations via the ear ossicles of the middle ear to the site of hearing (the cochlea of the inner ear). In amphibians and some reptiles there is no external ear and the tympanum is exposed at the skin surface.

Type specimen. The specimen used for naming and describing a species or subspecies. If this is the original specimen collected by the author who named the species it is termed a holotype. The type specimen is not necessarily the most characteristic representative of the species.
The term type is also used of any taxon selected as being representative of the rank to which it belongs. For example, the genus Solanum (potato) is said to be the type genus of the family Solanaceae.

Typical. Having most of the characteristics of a particular taxonomic group.

Tyrosine. One of the 20 Amino Acids common in Proteins. It has a polar ‘R’ group structure and is soluble in water.