<P> Fish reached substantial diversity during this time , leading the Devonian to often be dubbed the `` Age of Fish '' . The first ray - finned and lobe - finned bony fish appeared , while the placoderms began dominating almost every known aquatic environment . The ancestors of all four - limbed vertebrates ( tetrapods ) began adapting to walking on land , as their strong pectoral and pelvic fins gradually evolved into legs . In the oceans , primitive sharks became more numerous than in the Silurian and Late Ordovician . </P>
<P> Fish reached substantial diversity during this time , leading the Devonian to often be dubbed the `` Age of Fish '' . The first ray - finned and lobe - finned bony fish appeared , while the placoderms began dominating almost every known aquatic environment . The ancestors of all four - limbed vertebrates ( tetrapods ) began adapting to walking on land , as their strong pectoral and pelvic fins gradually evolved into legs . In the oceans , primitive sharks became more numerous than in the Silurian and Late Ordovician . </P>
which period is known as the age of the fishes
which period is known as the age of the fishes
the Devonian
the Devonian