Question

Paedomorphosis is seen in
(a) Oikopleura
(b) Salpa
(c) Balanoglossus
(d) Branchiostoma

Answer 1

Hint: They are bioluminescent species belonging to a group of species consisting of a very small genome from the genus Tunicata and are marine in habitat with the specific characteristic feature is the formation of marine snow.

Complete Step by Step Answer:
Paedomorphosis is the process that leads to the change in the traits and characters of an individual from their ancestors due to a certain amount of time period. This process is mostly seen in the case of Oikopleura as the larval stages develop into an adult.
- Paedomorphosis is the combination of two processes neoteny and paedogenesis.
- Neoteny is also called juvenilization where the organisms develop at a very slow rate physically. It is generally seen in the case of humans.
- Paedogenesis is also called progenesis where the process of sexual reproduction is fast- forwarded.
- Paedomorphosis is the stage of retention of the larval stage which then develops into an adult as seen in the case of salamanders.
- This process of retention occurring in neoteny and paedogenesis plays an important role in the evolutionary and developmental biology.
- Oikopleura is the sea-squirt that develops a layer of mucus around them every 24 hours when the temperature reaches around 20 degrees celsius.
- They develop a fine mesh-like structure of mucus around themselves so as to allow only fine particles to enter like bacteria.
- The genome in them is very small, around 75 base pairs.

So, the correct answer is ‘(a) Oikopleura.

Note: 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.