~Cnidarians include corals, jellies, and hydras. These animals are diploblastic, radially symmetric, and have a single opening that serves as both mouth and anus (incomplete digestive system).include sessile and motile forms, including hydras, coral, and jellies. Most exhibit simple, diploblastic, radial body plans.
Have a gastrovascular cavity.The body wall of a cnidarian has two layers of cells: an outer layer (epidermis) and an inner layer (gastrodermis). Digestion begins in the gastrovascular cavity. Flagella on gastrodermal cells keep the contents of the cavity agitated and help distribute nutrients. Between the two tissue layers is the mesoglea. have Cnidocytes and Nematocysts
~Platyhelminthes (Flatworms) (including tapeworms, planarians, and flukes) have bilateral symmetry and central nervous system. But they have no body cavity (acoelomate).Phylum Platyhelminthes
live in marine, freshwater, and damp terrestrial habitats Triploblastic; acoelomates. Flattened dorsoventrally and have a gastrovascular cavity
Gas exchange takes place across the surface, and protonephridia regulate the osmotic balance
~Mollusca-non-segmented.All molluscs have a similar body plan with three main parts:
Muscular foot is used for movement.
Visceral mass contains most of the internal organs.
Mantle is a fold of tissue that drapes over the visceral mass and secretes a shell.
Mantle cavity houses gills, anus, and excretory pores.
Radula used to scrape up food.
~Annelids are segmented worms distinguished from other worms by body segmentation. Earthworms are familiar annelids but also include marine and freshwater species.
~Echinoderms- such as sand dollars, sea stars, and sea urchins. Aquatic animals that are bilaterally symmetrical as larvae but not as adults. They move and feed by using a network of internal canals to pump water to different parts of their body.
~Sponges- sedentary animals from the phyla Calcarea and Silicea (formerly Porifera), live in fresh and marine waters
Lack true tissues and organs