Post date: 16-Feb-2012 12:20:23

The survival advantage gained by organisms with brains is the ability to exploit time. The ability to predict the future in terms of resources and dangers, and to act pre-emptively.

Clearly species that developed brains gained a significant survival advantage.

E.coli is a unicellular organism with the most simple of nervous systems. It is capable of sensing energy sources, nutrients and toxins, storing and evaluating the information and make a final decision keep swimming or roll (to alter direction).

Plants don’t need brains because they don’t move. Simple nervous systems connect sensory mechanisms directly to motor neurons. More complex brains are about exploiting time to take physical action. Brains are about using information from different times (seconds through years) to coordinate action. When brains compete in a Darwinian way it becomes about speed. Brains are about exploiting time, to take physical action, faster than the other brain.

If brains are about intelligence then this assumption leads to a natural definition.

Brains exist because the distribution of resources necessary for survival and the hazards that threaten survival vary in space and time. There would be little need for a nervous system in an immobile organism or an organism that lived in regular and predictable surroundings. In the chaotic natural world, the distribution and localisation of resources and hazards become more difficult to predict for larger spaces and longer spans of time.”

Allman in Evolving Brains pg 2

"All brains …… receive a diverse array of inputs that must be combined in such a way as to produce a very much smaller set of behavioural outcomes

Allman in Evolving Brains pg 6