Phylum Cnidaria Cnidos = “Stinging Needle”

1. Phylum CnidariaCnidos = “Stinging Needle” www.onacd.ca

2. BC jellyfish and sea pen

11. Coral • Water temperature must be at least 25 degrees Celsius to survive!!! • The Great Barrier Reef in Australia can be seen from outer space! • The remains of billions of individual creatures! • Some coral reefs are 300 metres thick • Some coral reefs are 25000 years old!

19. Coral • Water temperature must be at least 25 degrees Celsius to survive!!! • The Great Barrier Reef in Australia can be seen from outer space! • The remains of billions of individual creatures! • Some coral reefs are 300 metres thick • Some coral reefs are 25000 years old!

21. OUCH!

22. Stings from a Portuguese Man-of-War

24. 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

25. Characteristics - Phylum Cnidaria • Acoelomates & therefore do not possess any true body systems or organs. • 2 germ layers include ectoderm (protection), endoderm (inner lining) • and mesoglea (not a germ layer-it’s the jelly!!!) • Radial symmetry

26. Characteristics - Phylum Cnidaria • Tentacles • Capturing food with stinging cells (cell:cnidocyte with nematocysts) • Transportation • 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

27. NERVE NET • The first animals to have nerve cells. • The nerves form a “nerve net” • There is no brain • There is no cephalization (a bunching of nerve cells to form a brain)

28. 2 Body Types Polyp Medusa

29. Mouth and Anus Tentacle Tentacle Gastrovascular Cavity Calcified Shell (Coral) Note: This diagram shows the GVC in the polyp body type. Gastrovascular Cavity (GVC) • digestion, circulation, respiration and excretion. • Cons: • only one opening….. The mouth is the anus….. • Body systems - not separated or specialized

30. GVC • Digestion: glands release enzymes into body cavity • Circulation: via currents generated by body movements & flagella on endodermal cells • Respiration & Excretion: via diffusion because ectoderm & endoderm are in direct contact with the water

33. Cnidocyte with the Nematocyst

36. The stinging cells: Nematocysts • Function: to ward off predators and attack prey • Location: end of tentacles • Special cells called cnidocytes • Contain organelle called nematocyst • Produce a toxin • Action: Releases a barbed needle that penetrates the flesh and injects toxins when stimulated A discharged nematocyst

37. 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. (if this was an anemone the polyp would settle on the ocean floor and become a new polyp…. See picture of brooding anemone on next slide) #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

38. Brooding Anemones - very common – Other polyps form off existing polyps, break off and then settle on the ocean floor –Asexual reproduction!

39. Ecological Importance of Cnidarians • Filter and clean the water • Coral die as water temperature increases or decreases. • Death of coral often precedes death of entire ecosystems

40. Symbiotic relationships of cnidarians • Coral – a colony of polyps in symbiosis with algae • Clownfish and anemone . Benefit to clownfish: stinging cells do not harm the clownfish, but make the fish toxic to other fish…provide protection and shelter Benefit to anemone: clownfish clean the anemone

41. Killer Cnidarians The Portuguese Man O’ War • a colony of specialized polyps and medusas (not a single jellyfish) • sting - 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

42. A common sign to observe near Australian Beaches

43. 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 as well as a more developed eye 0.1 mm across 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

44. JellyFISH OUT OF WATER

45. http://ca.youtube.com/watch?v=Fm3EmkWMeHY (part 1 cnidaria) • http://ca.youtube.com/watch?v=QvUZJh9MHt8 (part 2 cnidaria) • http://ca.youtube.com/watch?v=6zJiBc_N1Zk (nematocyst firing) • http://ca.youtube.com/watch?v=Dm98n3908QM (swimming anemone) • http://ca.youtube.com/watch?v=_jNwWQtLeY4 (fighting anemone) • http://ca.youtube.com/watch?v=JoMCTvRkvxo (national geographic jellyfish) • http://ca.youtube.com/watch?v=JoMCTvRkvxo(anemone/clownfish partnership) • http://www.youtube.com/watch?v=grTN7BIbzfY comb jellyfish