DENDROLOGY

Detailed explanation-1: -Fish are aquatic vertebrates with a skull, a vertebral column supporting a medial septum dividing the fish into two lateral halves, and lateral longitudinal muscles segmentally arranged in blocks, or myotomes.

Detailed explanation-2: -The earliest vertebrates were jawless fish, similar to living hagfish. They lived between 500 and 600 million years ago. They had a cranium but no vertebral column.

Detailed explanation-3: -The phylum chordata (animals with backbones) is divided into five common classes: fish, amphibians, reptiles, mammals and birds. Show examples of these groups and explain the characteristics that make one different from another.