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Sponges Cnidarians Flatworms Roundworms
Kingdom Animalia Sponges Cnidarians Flatworms Roundworms
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Sponges Assymetrical Freshwater or saltwater Sessile – do not move
Filter feeders No Nervous System Multicellular organization (no true tissues yet)
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Other Sponge Facts: Sponges can regenerate – replace lost body parts through mitotic cell division. Economic Importance: Commercial sponge harvesting for personal care industry.
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Sponge Reproduction: Asexually – fragmentation or budding
Sexually – sponges are hermaphrodites External fertilization Internal fertilization - eggs remain inside parent sponge’s body.
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Cnidarians – Stinging Animals
Radial Symmetry Mostly saltwater Corals Jellyfish Sea anemones Hydra
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Cnidarian Movement POLYP is sessile – does not move
MEDUSA is motile – squeezes bell (umbrella) to move uses simple ring of contractile tissue (not muscle tissue yet)
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Feeding Use tentacles to capture food.
Tentacles have NEMATOCYSTS – stinging cells that grab and immobilize prey using toxins. Waste products and undigested materials are expelled through the mouth.
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Organization Nerve net – conducts impulses from all parts of the body.
No brain. Two layers of tissues derived from endoderm and ectoderm
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Cnidarian Reproduction
Asexually – budding (polyp form) Sexually –have separate male and female medusae that produce gametes that join through external fertilization to produce polyps.
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Flatworms - Platyhelminthes
Bilateral Symmetry Free-living in freshwater or parasitic in a host Has all three layers (endoderm, mesoderm, ectoderm) Acoelomate – no body cavity.
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An Important Group Many nasty parasitic infections. Dugesia Tapeworms
Flukes
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Flatworm Feeding Free living flatworms are scavengers.
Parasitic flatworms use specialized structures (usually with hooks) to attach to a host.
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Respiration & Excretion
Excretion - Flame cells remove excess water Respiration - Oxygen diffuses into body cells directly.
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Flatworm Nervous Systems
First appearance of cephalization. Primitive brain. Eyespots
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Flatworm Reproduction
Sexually - Hermaphrodites – internal fertilzation. Asexually – fission – when damaged, regenerates new body parts. Proglottids – found in tapeworms – each is shed off individually.
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Roundworms - Nematoda Bilateral Symmetry
Free-living in soil or parasitic in a host Pseudoomate – false body cavity. Movement - Longitutdinal muscles produce a thrashing movement
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Respiration & Excretion
Respiration - Oxygen diffuses into body cells. Digestive wastes are excreted through the anus. Flame cells remove excess water through pores in body surface.
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Roundworm Feeding Have a simple digestive system.
Have a mouth and an anus Parasitic roundworms use specialized structures (usually with hooks) to attach to a host.
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An Important Group Many nasty parasitic infections in humans, livestock Importance and IMPORTANT AGRICULTURAL PEST Pinworms, Ascaris, hookworms, Trichinella
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