Describe the evolution of the nervous system of animals.

The simplest multicellular animals, sponges, do not have a nervous system, but they do not need it.

The next steps are jellyfish and the most primitive worms. Jellyfish are free-living predators and have neural networks that help them sense prey and avoid predators.

The simplest worms, or flatworms, have only two cell layers, but they have something that didn’t exist before, and this changed the path of evolution: the head.

In fish, the nervous system is well developed, with the brain, which is the control center of the body, and the dorsal nerve cord, which is the carrier of the message from the control center to parts of the body and back.