Phylum Porifera The “Pore Bearers” www.onacd.ca
Phylum Porifera : The SpongesA few examples Red Volcano Sponge Yellow Tube Sponge Stovepipe Sponges
Identifying Characteristics of the members of Phylum Porifera • Non-coelomates (therefore do not possess any true body systems although they do have highly specialized cells that perform many functions) • Mostly asymmetric (some exhibit radial symmetry) • Possess a GASTROVASCULAR CAVITY (GVC) • Filter Feeders : through pores and special cells that line the GVC • Posses a skeleton made up SPICULES composed of either calcium, silica or spongin • Hermaphroditic : can reproduce sexually (do not self fertilize) or asexually by regeneration or budding • Sessile (anchored to the ocean floor as an adult) • Found mainly in marine habitats
Basic Structure of a Sponge The Gastrovascular Cavity • Has only one opening • Serves two primary functions 1. “Gastro” digests and absorbs food and nutrients 2. “vascular” serves as a primitive circulatory system as it moves nutrients around to other parts of the body
Basic Functions of the Internal Cavity • To filter water as it passes through the sponge for food and oxygen (see collar cell enlargement) • To extract particles of food from passing water and digest food either in collar cell food vacuoles or by roaming amoeboid cells. • To get rid of waste products through the osculum
Collar Cells at work bringing in water and retrieving oxygen and food for the sponge
Ecological Importance of Sponges • Sponges provide shelter and food for other ocean creatures • Sponges can release chemicals that help to break up old shells • Because sponges are filter feeders they are very sensitive to water pollution as it will quickly clog their pores and destroy the sponge. Therefore a lack of sponges in a certain area is a good indication that there is pollution in the area and more of the ocean life is potentially at risk Sea Crab living inside a Fluorescent sponge
Economical Importance of Sponges • At one time there was a market for sponges to be used in the bathroom and the kitchen because of their ability to absorb water, however synthetic sponges have replaced this industry Sea sponge Skeleton to be used in the bathroom for washing
Super Cool Sponge Facts • Each species of sponge somehow knows exactly which day of the year the other members of its species will release their gametes into the water. This is how sponges are able to cross fertilize. • The Loofah “Sponge” sold in many stores is not actually a sponge at all…. It’s the inside of a plant known as a gourd! Purple Vase Sponge and a sea fan
Phylum CnidariaCnidos = “Stinging Needle” www.onacd.ca
4 Classes of Phylum Cnidaria HYDROZOA – Obelia, Hydra (above), Portuguese Man O War SCHYPHOZOA - Jellyfish CUBOZOA – box jellies (sea wasps) ANTHOZOA – anemones (above), corals, sea fans
Identifying Characteristics of the members of Phylum Cnidaria • Non-coelomates & therefore do not possess any true body systems or organs. 3 germ layers include ectoderm (protection), endoderm (inner lining) and mesoglea • Exhibit radial symmetry • Possess tentacles used in transportation and for capturing food and stinging cells called nematocysts. • Possess a Gastrovascular Cavity (GVC) • Primitive Nervous System (Nerve net) • Hermaphroditic : can reproduce sexually (do not self fertilize) or asexually by regeneration or budding • Have a motile (medusa) and a sessile (polyp) stage in their lives • Found in marine habitats
Mouth and Anus Tentacle Tentacle Gastrovascular Cavity Calcified Shell (Coral) Note: This diagram shows the GVC in the polyp body type. Gastrovascular Cavity (GVC) • The inner cavity responsible for digestion, circulation, respiration and excretion. • Disadvantages of having a GVC include: • There is only one opening….. The mouth is the anus…..
2 Body Types Present in Phylum Cnidaria • Polyp • Sessile (no movement as they are anchored to the ground)) • Tentacles face up • asexual • Ex. Hydra, sea anemones, coral • Medusa • Motile • Tentacles face down • sexual • Ex. Jellyfish, sea wasps
The stinging cells: Nematocysts • Nematocysts are most commonly located at the end of tentacles • Are composed of special cells called cnidocytes that produce a toxin • When a trigger is stimulated it releases a barbed needle that penetrates the flesh and injects toxins. • Nematocysts are used to ward off predators or attack prey A discharged nematocyst
Life cycle of a typical Jellyfish #1-10 exhibit the formation of the polyp life form. #11 shows the polyp undergoing asexual reproduction in the form of budding. The top of the polyp breaks off and goes on to form the medusa stage of the jellyfish’s life. #12-14 shows the formation of the adult medusa The medusa will then go on to produce and release egg and sperm into the water. The eggs will be cross fertilized by the sperm of another medusa and eventually develop into a new polyp This alternating between two life forms is termed ALTERNATION OF GENERATIONS
Brooding Anemones From a single anemone other polyps are forming which will eventually break off and settle on the ocean floor to form new anemones. This is why many of the same type of anemone are often observed in the same area as the new polyps are not capable of traveling far distances.
Ecological Importance of Cnidarians • Filter and clean the water • Form symbiotic relationships will other ocean life • Examples. • Clownfish and anemone (remember Finding Nemo?) • Coral will die as the temperature of the water increases. Death of coral often precedes death of entire ecosystems The clownfish are immune to the stinging cells of the clownfish anemone. Therefore the anemone provides protection and shelter for the clownfish and in turn the clownfish clean the anemone.
Super Cool Killer Cnidarians The Portuguese Man O’ War • Looks like a jellyfish but is actually a colony of specialized polyps and medusas • The sting from their tentacles causes excruciating pain and sometimes death • Named for its air bladder which looks like the sails of a Portuguese fighting ship Super cool fact: Loggerhead turtles are actually immune to their toxins and feed on the Portuguese Man O’ War Portuguese Man O’ War Physalia physalis
Box Jellyfish • Possess the most deadly venom (toxins) in the animal kingdom which cause anaphylaxis shock and death • In Nov. – April they are abundant in Australian waters but it is not known where they go for the winter • Through ultrasonic tagging it has been found that they sleep on the ocean floor between 3pm and dawn to conserve energy and avoid predators • Possess 22 very simple light sensing eyes Box Jellyfish Chironex flecker This jellyfish has had an ultrasonic tag attached (very carefully!) to it in order to help learn more about the migration patterns of these cnidarians