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The Simplest Animals

The Simplest Animals. Sponges Jellyfish Flatworms Roundworms. Many images from: www.oceanicresearch.org/.../cnidarian.html. The Simplest Invertebrate Phyla are: -without a skeleton -without segmentation:. Porifera (sponges)

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The Simplest Animals

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  1. The Simplest Animals Sponges Jellyfish Flatworms Roundworms Many images from: www.oceanicresearch.org/.../cnidarian.html

  2. The Simplest Invertebrate Phyla are: -without a skeleton -without segmentation: • Porifera (sponges) • Cnidaria (jellyfish, hydras, sea anemones, Portuguese man-of-wars, corals) • Platyhelminthes (flatworms, including planaria, flukes, and tapeworms) • Nematoda (roundworms, including rotifers and nematodes)

  3. I. Sponges http://sps.k12.ar.us/massengale/images/brac-sponges-21.jpg

  4. Why are sponges considered animals? • Early biologists thought they were plants!

  5. The most primitive of the simplest animals: Sponges • Phylum: Porifera- • Invertebrate (no backbone) • Asymmetrical • No true tissues or organs • All species -Aquatic • Adult is Sessile (do not move)

  6. Sponges have key characteristics of animals: • Heterotrophic • Multicellular • Adults are sessile- but some species can move up to 4mm/day(http://www.ucmp.berkeley.edu/porifera/poriferalh.html) • And sponge larvae have flagella

  7. Basic Body plan of a Sponge Asymmetrical & Sessile Vocabulary of sponge parts: • Osculum- Hollow cylinder shape, closed at bottom, opening at top called • Choanocytes ( collar cells) – flagellated cells that draw water into the sponge through pores in the body wall calledOstia. • mesohyl – jelly-like material separates 2 layers of cells

  8. Collar cells- w/ flagella beat water through the sponge

  9. Purple Tube Sponge Colonyon Dead Coralhead atRainbow Reef near Bimini, The Bahamas www.reefnews.com/.../photos/corals/sponges.html

  10. If Coral Reefs are in danger- are sponges that grow on them bad? • Animals that eat sponges and algae help to keep a healthy balance on the reef. • If there are too few of these animals, then the sponges and algae may take over. • Examples of algae eaters are Parrotfish, Sea Urchins, and Crabs. • Examples of sponge eaters are Hawksbill Turtles and Loggerhead Turtles. www.reefnews.com/.../photos/corals/sponges.html

  11. How does a sponge eat? • Sponge cells work together, pumping water through the body of the sponge. • The sponge eats the plankton, bacteria & organic material it filters out of the water as the water is pumped through the body of the sponge. • Amoebocytes-crawling cells that deliver nutrients from choanocytes to the rest of the body • Sponges are filter feeders! www.reefnews.com/.../photos/corals/sponges.html

  12. How does a sponge reproduce? 1. Asexual a. Budding- part of the parent pinches off & forms a new organism b. Gemmules – a reproductive structure in sponges, -produced in harsh conditions -a food-filled ball of amoebocytes in a protective coat c. Regeneration- regrowth of missing cells. 2. Sexual a. Sperm are released into water, enters next sponge through pores, choanocytes engulf sperm. Carry to ameobocytes, carry them to egg in mesophyl. Produces a flagellatedLarvae (immature form) b. Hermaphrodite-each sponge has both eggs & sperm

  13. A sponge treated w/ dye to show squirting action!

  14. Some sponges grow quite large. This barrel sponge is nearly large enough for the diver to climb right inside! Other barrel sponges get even bigger than this.

  15. Porifera represent transition from unicellular to multicellular life.

  16. II. Phylum Cnidaria • Hydra, • Jellyfish, • Sea Anemones, • some corals

  17. Cnidarians are animals with 2 tissue layers • Cnidarians are the simplest animals with nervous & muscle tissue. • They sting & eat their prey!

  18. Purple-Striped Jelly("Chrysaora Colorata"), Monterey Bay Aquarium, Monterey, California, USA

  19. Giant jellyfish(6-7 feet across) www.divester.com/.../

  20. Blue jellyfishMonterey Bay Aquarium. Monterey, California, USA

  21. Hydra (with bud) http://www.isi.edu/robots/self_heal_html/hydra.JPG

  22. Pink Hearted hydroids,members of the class Hydrozoa. They look like delicate plants but they are animals that sting and capture food.

  23. Fire Coralhas a potent sting that leaves an itchy rash on human skin. A kind of hydroid that encrusts other objects (including other corals).

  24. Sea Anemone library.thinkquest.org/.../01819/SeaAnemones.htm

  25. Tealia anemone a good example of an Anthozoan. Flower-like animals resemble plants, but they have a mouth at the center of their tentacles, & a primitive digestive system.

  26. Cnidarian Body Plan 2 types of bodies or Stages: Medusa –bell shaped, swims Polyp– vase-shaped, sessile 2 cell tissue layers- Epidermisoutside layer Gastrodermis inside layer -with Mesoglea (jelly) in between) 1 opening Gastrovascular cavity (gut) Many Tentacles with cnidocytes

  27. POLYP MEDUSA http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg

  28. How do Jellyfish eat? • Cnidocytes (special defensive cell) have Nematocysts (coiled organelle with stinging filament) • Tentacles push prey in mouth & into gastrointestinal cavity • Digestion is Extracellular, wastes expelled through mouth. http://www.emc.maricopa.edu/faculty/farabee/biobk/cnidaria_1.gif

  29. Jelly fish are the 1st animals to have nervous & muscle tissue Nerve Net -Nerve cells interconnect and form a nerve net throughout the body. Movement – using pulsing tentacles Cnidarians have both muscle fibers and nerve fibers, making these animals capable of directional movement.

  30. Cnidarian classes: 1. Hydrozoa ( 3,700 species) ex- Obelia, Portuguese Man-O War. 2. Cubozoa ex- box jellies, sea wasp 3. Scyphozoa “cup-animals” jellyfish • Anthozoa (6,100 species) “flower animals” like sea anemones, corals

  31. Deadly danger: Portuguese man o'war can in extreme cases provoke a cardiac arrest and death in particularly sensitive persons. www.dailymail.co.uk/news/article-1050187/Pict...

  32. Lucky escape: Jonathan Asplin was only saved from worse harm by his wetsuit Pictured: Horrific scars suffered by boy, 8, stung by deadly Man o' War on British coast www.dailymail.co.uk/news/article-1050187/Pict...

  33. The Freshwater Hydrozoan Hydra:Polyp with early and mature bud. www.micrographia.com/.../hydr0100/hydra-01.htm

  34. Sea Wasp The venom of an adult sea wasp is so powerful that the victim may not even have time to swim to shore. www.jyi.org/features/ft.php?id=189

  35. Box jelly http://www.visualdiving.com/pics/uw144_27.jpg

  36. Jellyfish Sting Treatment • Rinse with seawater. Avoid fresh water because it will increase pain. Do not rub the wound or apply ice to it. • For classic box jellyfish stings, apply topical acetic acid (vinegar) or isopropyl alcohol. • Remove tentacles with tweezers. • Apply shaving cream or a paste of baking soda or mud to the wound. Shave the area with a razor or knife and then reapply vinegar or alcohol. The shaving cream or paste prevents nematocysts that have not been activated from discharging toxin during removal with the razor. • Immobilize the extremity because movement may cause the venom to spread. • Hydrocortisone cream may be applied 2-3 times daily to relieve itching. • CPR may be necessary for all stings if the person stops breathing and/or no longer has a pulse. http://firstaid.webmd.com/wilderness-jellyfish-sting-treatment

  37. The animals we usually call jellyfish belong to the class Scyphozoa. -almost all are drifters. Some of the jellyfishes are big, measuring many feet across with long, trailing tentacles. Like other cnidarians, the tentacles are lined with stinging cells

  38. Anthozoa: Giant Green Anemone

  39. Jelly fish Reproduction: • Some reproduce asexually • especially in warmer temperatures. • (Hydra-budding) • Sexual reproduction- • lower temps • hermaphrodites. • Motile sperm, egg in ovary.

  40. And now for … worms… • The term "worm" has no systematic value whatsoever. • Basically, any elongated invertebrate can be called a "worm", regardless if it is or not related to similar creatures. • However, two of the most primitive types of organisms receive that common name: WORMS • Phylum Platyhelminthes -flatworms • Phylum Nematoda -roundworms www.kingsnake.com

  41. III. Platyhelminthes(flatworms) • Planaria (free-living predators) • Flukes (parasitic) • Tapeworms (parasitic)

  42. Flatworms (Platyhelminthes) • Bilateral symmetry • Are the simplest of animals to have bilateral symmetry • Body flattened, leaf or ribbon-like (dorsal-ventral) • All 3 tissues layers • Ectoderm, • Mesoderm • Endoderm • Acoelomate (No body cavity) – solid body • completely filled in with tissue.

  43. A pretty flatworm http://www.islandream.com/wakatobi/flatworm02.jpg

  44. A Planaria species www.fcps.edu/.../zoo00/zoo00/zoowor/platy.shtml

  45. Planaria sp. www.fcps.edu/.../zoo00/zoo00/zoowor/platy.shtml

  46. encyclopedia.farlex.com/Platyhelminthe A marine turbellarian flatworm • ribbonlike movement • body surface covered in mucus-covered cilia • The ripples create waves of mucus, through which the creature pulls itself smoothly forward, using the hairlike projections.

  47. Three common marine flatworms from south-eastern Australia.A: Paraplanocera oligoglena.B: Pseudoceros sp.C: Eurylepta fuscopunctatus.Photo: Bill Rudman.

  48. A Planarian is a free living hunter -hunts small organisms -eats with it’s Pharynx (a muscular feeding tube/opening) - 1 openinggastrovascular cavity -sac body plan, with mouth serving as both a mouth and anus (there is no anus).

  49. Body of a planarian No true Circulatory / Respiratory systems -cells exchange oxygen & CO2 directly from environment It looks like it has eyes: but these are just EYESPOTS Nervous System-cerebral ganglia serves as a simple brain- transmits signals down “ladder-like” nerve network. Can respond to light, chemicals, touch & water currents in the environment

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