Sponges are the simplest of all animals. They are multicellular, heterotrophic, have no cell walls, and have specialized cells.
Carnivorous- eat small crustaceans Sheet sponge
Adult sponges are sessile. They live attached to a single spot. CAN”T MOVE
Sponges are asymmetrical filter feeders Feed on : bacteria, unicellular algae, and protists through filter feeding.
IV. Phylum- Porifera (“pore bear”) – sponges – simplest of all animals A. Body Plan – asymmetrical, pores all over body with large hole on top called osculum where water is pumped through, Have no mouth or gut, Have no tissues or organ systems, Simple functions are carried out by a few specialized cells B. Protection: skeleton of spicules (glass-like material) or spongin (soft)
Asymmetrical? Have no front or back ends, no left and right sides –A large, cylindrical water pump –The body forms a wall around a large central cavity through which water flows continually
Protection- Silica (cells of glass offer protection and support
C. Feeding – filter feeders, trap microorganisms in water flow. 1. Collar cells - specialized cells that use flagella to move a steady current of water thru the sponge. Each collar cell digests its own food. 2. Archaeocytes - specialized cells that make spicules 3. Pore cells – Cells thru which water flows into the body of a sponge
Major Body Functions D. Respiration/ Circulation/ Excretion – water flow carries out all body functions (osmosis and diffusion) As water moves through the cavity: 1.Oxygen dissolved in the water diffuses into the surrounding cells 2. Carbon dioxide and other wastes, diffuse into the water and are carried away
Major Body Functions E. Response/Movement- no nervous system, do produce toxins, adults don’t move (sessile), larva swim F. Reproduction- sexually with internal fertilization between two different sponges or asexually by budding or fragmentation
Osculum A large hole at the top of the sponge, through which water exits The movement of water provides a simple mechanism for feeding, respiration, circulation and excretion
Water flow Collar Cell Spicule Pore cell Pore Epidermal cell Archaeocyte Osculum Central cavity Pores The Anatomy of a Sponge
Ecology of Sponges 1.Ideal habitats for marine animals such as snails, sea stars, sea cucumbers, and shrimp 2.Mutually beneficial relationships with bacteria, algae and plant-like protists
Adult sponge releases sperm into the water Sperm fertilize eggs inside the body of another sponge The zygote develops into a free swimming larva Sperm (N) Egg (N) Larva (2N) Mature sponge (2N) Larva attaches to a hard surface New sponge Haploid (N) Diploid (2N) FERTILIZATION MEIOSIS Sponge Life Cycle (Sexual Reproduction) Sponges are hermaphrodites.
Review Questions Answer the 4 questions on your own.
Asexual Reproduction-Budding A new polyp genetically identical to the parent is formed.
Lion’s Mane Jelly
Box Jelly Some have eyes!
Colony of polyps
Deadly within 3 minutes! Chironex fleckeri Found off the coast of Australia Over 100 deaths in the last 25 years
Orange Cup Coral Red Sea Fan
Sea Pen Feathery Hydroid
Fungiid Coral- this coral can move!
Mushroom Coral Giant Sea Fan
Solid Table Coral Staghorn Coral
Phylum Cnidaria –more complex than sponges A. Carnivorous animals with stinging tentacles around their mouths B. Simplest animals to exhibit symmetry – cnidarians have radial symmetry C. Simplest animals to have true tissues including nerves
Examples: hydra, coral, sea anemone Examples: jellyfish, portuguese man of war Cnidarians have two body forms Polyp - stationary, vase-shaped Medusa - swimming, cup-shaped
Examples: hydras, jellyfishes, sea anemones, and corals A. Hydrozoans: Most of life as polyp ex. hydra B. Scyphozoans: Most of life as medusa ex. jellyfish C. Anthozoans: Only polyp stage in the life cycle ex. corals and sea anemones
Simplest animal with true tissues. –soft bodied, have tentacles, radial symmetry, 1. Gut – gastrovascular cavity with one opening 2. Nerve net- detects stimuli 3. Hydrostatic Skeleton- movement and support with the use of muscles
The Polyp and Medusa Stages 1. Polyp - Stationary, Examples: Hydra, Coral, and Sea Anemone 2. Medusa- Swimming, Cup Shaped. Examples: Jelly Fish and Man O War
Epidermis Mesoglea Gastroderm Bell gut Mouth/anus Tentacles Mouth/anus Gut Polyp Medusa The Polyp and Medusa Stages 3 tissue layers
1. Feeding- kill small prey with stinging cells in tentacles, digest in gut, food in and waste out of one opening. 2. Respiration/Circulation/Excretion- all by diffusion (no true organs) 3. Response- have specialized sensory cells and nerve net to gather info and react to stimuli.
Response a. Statocysts: groups of sensory cells that help determine the direction of gravity b. Ocelli: eyespots made of cells that detect light
(Stinging Cell) (Stinging Structure)
4. Movement- propel themselves with water using hydrostatic skeleton 5. Reproduction- asexually by budding, sexually by external fertilization, sperm and egg are released and meet in water
IX. Ecology of Cnidarians A. Source of new drugs/chemicals sunscreen 855 B. Provide habitats for marine organisms C. Source of food for other organisms (like sea turtles) D. Symbiotic relationships with other organisms
Fertilization occurs in the open water, producing many diploid zygotes. Sperm (N) Egg (N) Haploid Diploid FERTILIZATION MEIOSIS Male medusa (2N) Zygote (2N) Polyp Budding polyp Young medusa Female medusa (2N) Each zygote grows into a ciliated larva. The larva eventually attaches to a hard surface and develops into a polyp. Swimming larva The polyp buds to release young medusas. Adult medusas reproduce sexually by releasing gametes into the water. Jellyfish Life Cycle (Sexual Reproduction)