Re: What are the advantages of cephalization to an organism?

What are the adaptive benefits of cephalization?

Cephalization in the development of a functional “head” end of an 
organism. Several things results from this developmental step. First, is 
the concept of polarity. The organism now demonstrates significant 
differences along the length of its body, so that a head end can now be 
distinguished from a tail end. These differences represent enhanced areas 
of specialization – a mouth in front, a stomach in the middle, an anus at 
the end. Regional specialization allows for more efficient concentration 
of effort in one region rather than having the entire body fulfill that 
function. Yes, there are some regional specializations in non-cephalad 
creatures – but the design concept does not really take-off until polarity 
becomes an important part of the body plan.

One example of polarity in the body plan is cephalization – the formation 
of a head and a brain. In this early stage, the brain is still relatively 
simple, but through polarity it shows differences from the rest of the 
nervous system. What are the advantages of having a brain? It allows for 
the development of sense organs (sight, hearing and smell) that can be 
used to identify threats, or opportunities, before the creature comes into 
contact with them. Notice that these major sense organs (eyes, ears, nose) 
are located near the brain since they are effectively elaborations of the 
brain. The sense of touch (pain and temperatures) occurs all over the body 
and does not even require a brain for interpretation (a reflex is a 
response to a touch sensation that has not been interpreted by the brain).

With the ability to sense the environment at a distance, the organism also 
makes use of the brain to develop a more intricate behavioral script. At 
the simplest level the “behaviors” may not seem like much. But, this 
simple brain allows for a variety of responses to environmental 
circumstances. An organism with a brain with not always respond to a 
stimulus in exactly the same way – an organism without a brain will. The 
simplest little behavioral complexity would give the organism a survival 
advantage over creatures that always respond in exactly the same fashion 
(plants, or plant-like animals).