Question

Regeneration can be best studied in
(a) Planaria/Dugesia
(b) Amphioxus
(c) Earthworm
(d) Sponge

Answer 1

Hint: Regeneration is a mode of asexual reproduction in which the organism can be cut into parts and each part grows into a complete organism. This is due to the capability of cells at the site of the cut which can replicate and regenerate the lost part.

Complete answer:
Regeneration can be best studied in planaria because they contain an inner lining of pluripotent stem cells that can differentiate and form new organs. Planaria are found in both freshwater and seawater, in terrestrial conditions they are found in humid areas.
- Planaria are flatworms that can feed on both living and nonliving animals.
So the correct answer is option (a) ‘Planaria/Dugesia’.

Additional information:
Amphioxus: Amphioxus is also called lancelets, which are the members of the phylum Chordata. These tiny marine organisms tend to live in warmer coastal areas.
- They spend most of the time at the bottom of oceans where they filter the water which goes through their gills for food.
Earthworm:
- Earthworms are segmented invertebrates. They are capable of producing both eggs and sperm which makes them compatible with sexual reproduction.
They are also known as ‘farmers friends’ as it makes the soil fertile. They are also used for making compost fertilizers.
Sponge: Sponges are not capable of locomotion and also lack a digestive and respiratory system. Their major source of food is bacteria which they capture when the water passes through is pores.

Note:
- The scientific name of planaria is Platyhelminthes and the scientific name of earthworm and sponge are Lumbricidae and Porifera respectively.
- Approximately, there are 2,700 different kinds of earthworms in which all kinds prefer food, moisture, oxygen, and a favourable temperature for proliferation.
- Totipotency is the capability of cells to regenerate an entire organism from a single cell, where unipotent cells are only capable of replicating into the same type of cell.