Cnidaria is a phylum of simple, aquaticanimals that are predominantly marine. They include jellyfish, sea anemones, corals, and hydras. Cnidarians are known for their unique stinging cells called cnidocytes, which they use for capturing prey and defense.
Characteristics of Cnidaria:
Radial Symmetry:Cnidarians exhibit radial symmetry, which means their body parts are arranged around a central axis.
Cnidocytes: Specialized stinging cells called cnidocytes contain nematocysts, which are used for immobilizing prey.
Two Body Forms:Cnidarians exist in two body forms - the polyp form (such as sea anemones and corals) and the medusa form (such as jellyfish).
Nerve Net: They have a simple nervous system in the form of a nerve net, which allows them to respond to stimuli.
Simple Digestive Cavity:Cnidarians have a sac-like body with a central digestive cavity with a single opening serving as both the mouth and anus.
Energy - A. Energy is involved in all physical and chemical processes. It is conserved, and can be transformed from one form to another and into work. At the atomic and nuclear levels energy is not continuous but exists in discrete amounts. Energy and mass are related through Einstein's equation E=mc 2 . B. The properties of atomic nuclei are responsible for energy-related phenomena such as radioactivity, fission and fusion. C. Changes in entropy and energy that accompany chemical reactions influence reaction paths. Chemical reactions result in the release or absorption of energy. D. The theory of electromagnetism explains that electricity and magnetism are closely related. Electric charges are the source of electric fields. Moving charges generate magnetic fields. E. Waves are the propagation of a disturbance. They transport energy and momentum but do not transport matter.
Relate temperature to the average molecular kinetic energy.