Question

Explain the term Neoteny.

Answer 1

Hint: It is the process of delaying the growth of somatic cells except for the reproductive parts. If the maturation of the somatic cells is delayed then physical maturation is delayed too. In this, sexual development remains in constant phase which means germs cells produce at a normal rate.

Complete Step by Step Answer:
- Neoteny term first given by Julius Kollmann, as he explained about axolotl larva in its maturation remains in a tadpole form and completes its aquatic stage with gills unlike other adult amphibians like toads and frogs.
- Neoteny is defined as a delayed somatic development with constant reproductive development. Neoteny is related to the developmental process that is sexual development attributed to the larval phase of an organism. Neoteny is a prolonged Juvenile phase of adolescence.

Additional information:
Neoteny is of three types:
- Obligate Neoteny - also called permanent neoteny, the organism does not undergo metamorphosis and remains in the larval form its entire life. e.g. Siren
- Inducible neoteny - for some time (years) the organism will be in its larval form and later convert in adult form. e.g. Ambystoma.
- Facultative Neoteny - occurs in individuals as a result of environmental factors. Here, metamorphosis is optimal and conditional.
- In humans neoteny is characterized by delaying body development resulting in features such as a large head, a flat face, and short arms. these changes brought by sexual selection in human evolution.
- Neoteny is also seen in domestic animals like cats and dogs because of more resources and less competition. So animals release less energy for obtaining these resources.

Note: A metamorphosis is a developmental event in which the thyroid hormone triggers these events. Poor secretion of thyroid glands and no response of the larval tissue to the hormone are responsible for neoteny. The term neoteny was derived from the Greek word neos, meaning ‘young’ and teinein, meaning ‘to extend or to stretch’. Although the term was originally taken from the German word Neotenie. This term Neoteny was first discovered and proposed by Julius Kollmann in 1885. Later in 1926 neoteny was introduced to be an important process in humanization by Louis Bolk.