Question

what is the association between bidy symmetry type and nervous system type

Answer 1

As we know organisms are classified based on their symmetry into asymmetric, radial symmetric and bilateral symmetric organisms. In bilateral symmetry their body can be divided into two equal halves only on one single plane, whereas in radial symmetry the body can be divided into equal halves along any plane.

We as human and all other complex organisms are bilaterally symmetrical and our control and coordination occur via the nervous system (the brain and spinal chord). i.e., the anterior region of us is demarcated for control and coordination (cephalization). On the other hand in radial symmetric organisms like star fish and cnidarians etc., there is no specific cephalization. Instead they have nerve nets, a network of nerves that drapes throughout the skin and radial nerves, nerves that radiate from a central ring and spread to the appendages(as in sea stars).

So, hence we can say that organisms with complex nervous system are bilaterally symmetrical.