Neuropeptides in the autonomic control of gut and circulation in fish and other non-mammals – Susanne Holmgren (p.20)

The study of physiological mechanisms from a comparative point of view can be particularly rewarding. Amazing similarities and fascinating differences between animal groups and species help the understanding of evolutionary mechanisms. The recurring similarities in a particular control system indicate a strong evolutionary pressure to maintain certain features, and point to their crucial importance in the persisting system.