1. Tree of Life The tree of life according to Ernst Haeckel, 1891

2. How does Porifera fit in? Porifera Other animals unknown common ancestor eukaryote multicellular heterotrophic Blastula stage cellular level of organization choanocytes 3 body types

3. How does Cnidaria fit in? Porifera Other animals unknown common ancestor eukaryote multicellular heterotrophic Blastula stage cellular level of organization choanocytes 3 body types Cnidaria

4. Phylum Cnidaria

5. Level of Organization Tissue cells are organized into tissues and work together to accomplish physiological functions

6. Tissue Layers Diploblastic = 2 germ layers endoderm  gastrodermis ectoderm  epidermis mesoglea gelatinous matrix between the 2 layers epidermis mesoglea gastrodermis gastrovascular cavity

7. General Body Plan sac-like body (only 1 opening) Food and waste go in/out the same opening  no anus! water within GVC acts as a hydrostatic skeleton Gastrovascular cavity mouth oral surface aboral surface epidermis gastrodermis mesoglea

8. General Body Forms 2 different body forms are usually present in the life cycle: polyp & medusa ** one animal may pass through both forms during its life **

9. General Life Cycle

10. Radial Symmetry - body parts are arranged concentrically around an oral-aboral axis oral aboral

11. Nematocysts specialized stinging organelles found within cnidocytes (cells) cnidocytes are located in epidermis A cnidocyte with a nematocyst within it

12. Nematocysts nematocysts are like “mini-harpoons” cnidocil senses movement & acts like a “trigger” can inject poison, coil around prey, or be adhesive functions: - prey capture; defense UndischargedDischarged cnidocil cnidocyte nematocyst

13. Colony formation colony formation is common (colonial animals) occurs via asexual reproduction (e.g. fission) individual polyps are connected to one another by the GVC individual polyp

14. Physiology Feeding –nematocysts within cnidocytes –tentacles Digestion –extracellular (in GVC) –intracellular (by gastrodermal cells) –incomplete system (no anus) Gas exchange & Excretion –these systems are absent

15. Physiology Nervous System –nerve net (no central nervous system= no brain) –sense organs –statocysts (equilibrium organs) –ocelli (photosensitive organs) Skeletal System –water in GVC acts as a hydrostatic skeleton

16. Physiology Reproduction Asexual –budding –longitudinal fission –pedal laceration (e.g. sea anemones)

17. Physiology Reproduction Sexual –usually dioecious (separate sexes  e.g. humans) –monoecious (both male + female gonads in 1 individual) –results in Planula larva

18. Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Anthozoa

19. Class Hydrozoa medusa & polyp body forms Fire coral

20. Class Hydrozoa medusa & polyp body forms most are colonial  colonies are formed of individual zooids a single zooid

21. Class Hydrozoa many of these colonies show polymorphism  this is where there are several different types of polyps/zooid and each type is specialized for a different function e.g. gastrozooids = feeding polyps e.g. dactylzooids = defense polyps  all the zooids within a colony are genetically identical  these different zooids work together in the colony

22. Class Hydrozoa gastrozooid gonozooid - a sessile colony showing polymorphism entire colony

23. Class Hydrozoa gastrozooid dactylzooid - a Portugese Man-o-war is a floating hydrozoan colony showing polymorphism entire colony pneumatophore

24. Class Hydrozoa- life cycle sexual reproduction asexual reproduction

25. Class Hydrozoa asexual reproduction Hydra is an example of a solitary, freshwater hydrozoan sexual reproduction gonads bud

26. Class Scyphozoa “true” jellyfish medusa & polyp body forms thick mesoglea

27. Class Scyphozoa- life cycle egg sperm larva scyphistoma strobila ephyraAdult medusa

28. Class Anthozoa polyp body form ONLY all marine

29. Class Anthozoa some are colonial  colonies are formed of individual zooids some are solitary

30. Class Anthozoa Sea anemones

31. Class Anthozoa Soft Corals Sea pen Sea pansy

32. Class Anthozoa Stony Corals

33. Class Anthozoa- life cycle egg sperm larva Sexual reproduction

34. Class Anthozoa- life cycle asexual reproduction fission pedal laceration fission

35. How does Cnidaria fit in? Porifera unknown common ancestor eukaryote multicellular heterotrophic Blastula stage cellular level of organization choanocytes 3 body types Cnidaria tissue level of organization diploblastic 3 classes:Hydrozoa, Scyphozoa, Anthozoa 2 body types: polyp, medusa

36. Symbiosis Mutualism – Corals contain endosymbiotic algae called zooxanthellae the zooxanthellae photosynthesize and provide food for the coral while the coral provides a safe home zooxanthellae

37. Symbiosis Mutualism – Many species of anemone fish (clown fish) live within anemones and are immune to their stinging nematocysts the fish may lure in other fish for the anemone to capture and eat, while the anemone provides protection and a home

38. Coral Reefs What are they? stony corals lay down a calcium carbonate skeleton these skeletons are laid down on top of one another and over thousands of years, form large calcium carbonate structures these large structures, along with the plants and animals that inhabit them, are known as coral reefs Where do they form? in optimal conditions for their zooxanthellae  shallow, warm, nutrient-poor waters

39. Importance of Coral Reefs one of the most productive ecosystems although the water is nutrient-poor “hot spots” for biodiversity

40. Threats to Coral Reefs over-enrichment of nutrients from sewage and agricultural run-off overfishing of herbivorous fish global warming (leads to coral bleaching where corals expel their zooxanthellae)