Final answer:
Bilateral symmetry in animals facilitated the evolution of cephalization, which involves the concentration of sensory and neural structures in the head.
Step-by-step explanation:
Evolution of Bilateral Symmetry and Cephalization
The evolution of bilateral symmetry is closely linked to cephalization, which denotes the development of a concentration of nervous tissues and sensory organs at the anterior, or head end of an organism. Bilateral symmetry allows an organism to have distinct right and left sides that are mirror images of each other and is an essential step in animal development. This symmetry facilitates streamlined and directional motion, promoting active and controlled locomotion and leading to the evolution of a centralized nervous system at the head of the organism, a trait referred to as cephalization.
Cephalization is significant because, in a bilaterally symmetrical animal, the head typically encounters new environments first, necessitating the organization of sensory and neural structures in this region. The development of bilateral symmetry and the subsequent cephalization allowed for increased sophistication in behaviors such as resource-seeking and constructing predator-prey relationships. Hence, the evolution of bilateral symmetry was a precursor to cephalization.