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Sponges. Ms. Moore 1/31/13. What is a sponge?. Placed in the phylum Porifera (pore bearers) Live entire adult life attached to a single spot (sessile) Why are sponges animals? Multicellular Heterotrophic No cell walls Few specialized cells. Form and Function.
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Sponges Ms. Moore 1/31/13
What is a sponge? • Placed in the phylum Porifera (pore bearers) • Live entire adult life attached to a single spot (sessile) • Why are sponges animals? • Multicellular • Heterotrophic • No cell walls • Few specialized cells
Form and Function • Sponges are asymmetrical = no front/back or left/right • Act as a cylindrical water pump • Choanocytes: specialized cells that use flagella to move a steady current of water through the sponges • Osculum: a large hole at the tope of the sponge where water leaves • Water flow is the simple mechanism a sponge uses for feeding, respiration, circulation, and excretion • Spicule: spike shaped structure made of calcium carbonate or silica • Archaeocytes: specialized cells that make up spicules • Spongin is present in soft sponges; network of flexible protein that CAN make up a sponge skeleton
Feeding • Sponges are filter feeders that silt microscopic food particles from water • Digestion takes place intracellular (within the cells). • Choanocytes engulf food particles and digest them; particles are then passed on to archaeocytes to finish off digestive processes
Respiration, Circulation & Excretion • Sponges rely on the movement of water to carry out body functions. • As water moves through sponge cells, O2 can diffuse into cells and CO2 along with wastes can diffuse out of the cells and into the surrounding water.
Response • Sponges do not have a nervous system • Some produce toxins that warn predators and make them inedible. Two nudibranch molluscs, Helgerta sp., feeding on a thinly encrusting red sponge and an algal mat
Reproduction • Sexually or Asexually • Sexually: • A sponge can produce both sperm and egg on the same plant, but not at the same time • Internal Fertilization: process where sperm fertilizes the egg inside the sponge body; sperm swims in water to a new sponge, then archaeocytes carry sperm to the egg (attached to walls of sponge) • Asexually: • Budding: part of parent breaks off and grows into a new and identical sponge • Gemmules: groups of archaeocytes surrounded by spicules; can survive freezing temperatures and drought; grow when conditions are favorable
Ecology • Ideal habitats for snails, sea stars, sea cucumbers, and shrimp. • Photosynthetic organisms can live in a sponge and provide it with sufficient O2 and food while the sponge provides the organism a place to live. • Spicules can direct sunlight to organisms living in the sponge when sunlight is low or limited.
Mini Lab • Create a booklet showing the body plan, water flow, and reproduction of a sponge. • Make sure you have the illustration regarding early development (blastula) in your notes from yesterday. • Exit Ticket • Making connections: What type of relationship would a shrimp and sponge share? Who would benefit? Why? What about a star fish and sponge?