Question

Lateral line system found in fish has been lost in amphibians due to
A. Development of limbs
B. Change over to herbivorous feeding
C. Occurrence of metamorphosis in frog
D. Evolution of terrestrial habit

Answer 1

Hint: The lateral line system is an extremely valuable system only for aquatic animals’ movement. In addition, amphibians reside on land as well as water and they already possess a system to direct their movement on terrestrial habitat and thus, the system is not much required.

Step by step answer:The lateral line system is a type of sensory system found in fishes and aquatic amphibians. This system is unique to aquatic vertebrates. With the lateral‐line system, fishes are able to measure the relative movements between their bodies and the surrounding water at each of up to several thousand sensory organs. The ability to detect the flow of water using the hair cells of the lateral line system is a unique feature of this system. Fishes use their lateral line to locate prey, escape from their predators, and form cohesive patterns.
Amphibians are creatures that are able to reside on both land and water. As known, the lateral line system is required for locomotion in water by the aquatic species. So, if the animals reside on land, they will not require such a system of sensory organs for movement and direction. As a part of evolution, amphibians evolved over time to adapt to the terrestrial environments around them and this system of sensory organs appeared due to its uselessness.
Hence option D is correct.

Note: We should know that the sensory ability is achieved via modified epithelial cells also known as hair cells. These cells respond to the displacement caused by motion and convert these signals into electrical impulses through excitatory synapses. Lateral lines play an important role in schooling behavior, predation, and orientation in aquatic vertebrae, mainly fishes.