AP BIOLOGY

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: -Cephalized organisms display bilateral symmetry. The nervous system and sensory organs are present near the head, located at the front or anterior end of the animal, and the posterior end contains the tail.

Detailed explanation-3: -Vertebrate animals are highly cephalized organisms as they have well-developed brains, nervous systems, etc. Animals having bilateral symmetry are generally cephalized.

Detailed explanation-4: -Cephalization: This simply means the presence of a head. Cephalization occurs in all bilaterally symmetrical animals because there is an advantage in having the end that goes first, as the animal moves, fitted out with sense organs-on the premise that it is better to know where you are going than where you have been.

Detailed explanation-5: -Bilateral symmetry is characteristic of the vast majority of animals, including insects, fishes, amphibians, reptiles, birds, mammals, and most crustaceans.