Question

1. Explain how the adaptations of cartilaginous fishes make them better predators.
2. What is an ammocoete? What is the possible significance to the evolution of vertebrae?

Answer 1

1. The class chondrichthyes consists of the cartilagious fishes, includes sharks, batoids and chimaeras or ratfish. These are found in some oceans and fresh water environments. However adaptations have made them succesful predators. The senses of many sharks have been well developed, keen sense of hearing have made them locate prey as far as 250meters. Sharks can reduce and expand their pupils.

2. Lamprey larvae also called as Ammocoetes is the larvae stage of primitive lamprey serves to illustrate much malignated concept of ontogeny recaptulating phylogeny by resembling the more primitive chordata Amphioxus. The notochord, dorsal hollow neural tube , phayngeal gill slits and other morphological characters distinguish chordata from other animals.