GEOLOGY

Detailed explanation-1: -The first fish were primitive jawless forms (agnathans) which appeared in the Early Cambrian, but remained generally rare until the Silurian and Devonian when they underwent a rapid evolution.

Detailed explanation-2: -Devonian period (410-360 million yrs ago; ‘age of fishes’) is marked by origin of amphibians and diversification and dominance of fishes on earth.

Detailed explanation-3: -Jawed fish now seem to have originated as early as the Great Ordovician Biodiversification, a period around 485 million to 445 million years ago when marine invertebrates ruled.

Detailed explanation-4: -A fossil fish that predates dinosaurs and was thought to have gone extinct has been found alive in the West Indian Ocean off the coast of Madagascar. The fish named coelacanth was accidentally rediscovered by a group of South African shark hunters, according to reports.