Sponges and Cnidarians Chapter 33

Phylum Porifera-“pore-bearers” NO organs or body systems Asymmetry All are SESSILE; they do not move Sponges are filter–feeders because they cannot search for food. They have 2 cell layers. Body structure resembles a hollow cylinder that is closed at the bottom and has an opening at the top called an OSCULUM.

Sponge structure Pores called OSTIA allow food and oxygen to enter the body. The inner layer is lined with flagellated collar cells called CHOANOCYTES. The beating of the flagella causes water to circulate into the sponge through its pores. AMOEBOCYTES- cells that can move around the sponge’s body carrying nutrients to other cells,

ASEXUALLY REPRODUCTION SIMPLE SKELETON: SPONGIN-soft SPICULES-hard ASEXUALLY REPRODUCTION budding regeneration SEXUAL REPRODUCTION Some are hermaphrodites-produce egg and sperm They can not self-fertilize.

Phylum CNIDARIANS (COELENTERATES= HOLLOW GUT) Jellyfish, hydra, coral, sea anemone, Portuguese man of war Tentacles have cnidocytes or stinging cells which help them paralyze and capture prey; also aid in protection When tentacles touch a food source a nematocyst shoots out to paralyze prey RADIAL symmetry Two layers of cells

Gastrovascular cavity -stomach for food digestion No head or brain Nerve net allow them to respond to the environment Two body forms POLYP-vase shape (sea anemone) MEDUSA- bell shape (JELLYFISH)

CLASS HYDROZOA PORTUGUESE MAN-OF-WAR HYDRA-live in freshwater Consist of a colony of animals working together Stings are extremely painful. HYDRA-live in freshwater

CLASS CUBOZOA Also known as box jellies for their cube shaped medusa

CLASS SCYPHOZOA Cup animals-jellyfish

Jellyfish life cycle

CLASS ANTHOZOA “flower animal” Sea anemone Mutualistic relationship with the clownfish Food and protection Coral Polyps die and leave hardened shells Coral reefs provide food and shelter for marine animals Mutualistic relationship with algae Algae produces food Coral provides protection and access to light

PowerPoints/Booklets Due May