Molecular basis of behavior in simple animals

Protozoa, sponges, ctenophores, and cnidaria have behaviors largely reliant on calcium ion based electrical impulses but their different forms of electrogenesis show increasing levels of complexity. The position of the ctenophores in the evolutionary tree of life is controversial; their muscle systems are well developed but their nervous system is a simple nerve net. On the other hand, many jellyfish have highly condensed nervous systems equipped with pacemaker cells that drive swimming. In hydrozoan jellyfish, these swim pacemakers have inhibitory inputs that allow the animals to trap food and escape predators. The nervous system of Aglantha digitale is complex enough for the animal to be able to perform powerful escape swims. However, such swims consume considerable amounts of energy and for most of the time the animal undergoes more energy efficient forms of swimming. Analysis of swimming in the deep-water jellyfish Colobonema, observed locally, suggests that it may be able to do the same thing. The aim is to account for these patterns of behavior in terms of the molecular components of the animal’s nerve circuitry.

Speaker: Roberet Meech, Univ. of Bristol