Is the nervous system in platyhelminthes more or less sophisticated than in cnidarians? What are the main neural structures found in flatworms? How is this neural organization important for the diversity of biological niches explored by species of the phylum?

Platyhelminthes present a more complicated nervous system than cnidarians, as the first neural chords with ganglia (grouping of neurons) appear, a characteristic of the evolutionary process of enhanced nervous complexity. In platyhelminthes one can note the starting of the cephalization process, with a concentration of neurons (nervous cells) in the anterior portion of the body and the appearance of photoreceptor cells in the ocelli.

With the enhanced capacity of these animals to perceive and to interact with the surrounds due to the increased complexity of their neural complexity, it is possible to find platyhelminthes in a variety of environments, containing the terrestrial, and with diverse ways of life, like those that are parasites and those that are free-living.