EVERYDAY SCIENCE

Detailed explanation-1: -Cephalization is an evolutionary trend in which, over many generations, the mouth, sense organs, and nerve ganglia become concentrated at the front end of an animal, producing a head region. This is associated with movement and bilateral symmetry, such that the animal has a definite head end.

Detailed explanation-2: -Cephalization is an evolutionary trend to concentrate sensory and neural organs anteriorly in a head. In the field of the neurosciences, it may be defined as the progressive growth of the (cephalic) nervous system during the evolution of animal life.

Detailed explanation-3: -Flatworms have a cephalized nervous system that consists of head ganglion, usually attached to longitudinal nerve cords that are interconnected across the body by transverse branches. Excretion and osmoregulation by flatworms is controlled by “flame cells” located in protonephridia (these are absent in some forms).

Detailed explanation-4: -Cephalization is derived from the Greek word kephale, meaning head. In evolutionary trends, cephalization is defined as the process involving the concentration of sensory and feeding organs such as nerve cells, mouth, and jaws at the anterior end and the development of the brain.

Detailed explanation-5: -Cephalization is first observed in Phylum Platyhelminthes.