Question

Axolotl is the name given to the larva of
(a) Silkworm
(b) Ambystoma
(c) Amphioxus
(d) Roundworm

Answer 1

Hint: Axolotl belongs to a class of organisms that can survive on both land and water. Axolotl exhibits neoteny, which is a unique phenomenon, wherein the adult organism retains some of its larval features and is not lost when it attains maturity.

Complete answer:
The larva of Ambystoma or tiger salamander is known as Axolotl. It has three pairs of external gills and a tail bearing caudal fin. Caudal fins help in swimming. They belong to the order Urodela of class Amphibia. Urodela is an order of tailed amphibians. They have been listed as critically endangered by IUCN. Even though they are the top predators in their lake ecosystem, recently this has not been the case. Introduction of large fishes in the lake followed by the draining and contamination of the lake, their population is declining. Also, in Mexico, they have been included in food menus and thus being captured by fishermen.

Additional Information: Some of the salient features of Axolotl are as follows:
-It exhibits sexual dimorphism where males and females can be distinguished externally. The male has a wider cloaca, longer tail, and narrow head. Females possess narrow cloaca and plump bodies.
-Fimbriae or fine filaments around the external gills increase the surface area for the exchange of gases.
-They are endowed with regenerative capacity. This involves the regrowth of any detached or damaged appendages within months.

So, the correct answer is ‘Ambystoma’.

Note:
-Amphioxus is a member of the subphylum Cephalochordata, where notochord persists throughout the life of an organism. It extends along the length of an organism’s body. Both the anterior and posterior ends are pointed, hence, commonly known as lancelets.
-Roundworms are the members of the phylum aschelminthes. They are unsegmented pseudocoelomates with a syncytial epidermis i.e epidermis is a continuous long layer with multiple scattered nuclei. Eg. Ascaris.
-Silkworms or Bombyx mori are insects which are extensively cultivated for silk fibres found in their cocoon.