Chimney SpongeDespite lacking nerves, muscles and a central nervous system, sponges are capable of organizing behaviours in response to external stimuli. an inflation/contraction response, or “sneeze”, as a coordinated response to stimuli. This combination of simplicity of form and sophisticated reactive responses prompted a group of researchers, led by Sally Leys of the University of Alberta, to investigate the means of sensory function. The results of this study may well have larger implications beyond an understanding of the mechanisms underlying the sneeze response in sponges. The sensory role of the cilia in the osculum may represent either a convergent role across all Metazoa, or an ancient evolutionary role for primary cilia. These findings of an organized array of sensory cells in sponges could represent a living example of the first sensory behaviours to have evolved in animals and may provide the key to understanding the possible mechanisms of evolution of sensory systems in the Metazoa.
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Nervous System