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Phylum Cnidaria. Phylum Cnidaria: Diagnostic Features. hydra, jellyfish, sea anemones, and corals fresh water & marine polymorphic (polyp & medusa forms) benthic & planktonic metazoans; tissue grade; diploblastic radiate predaceous. Cnidocytes - stinging cells with nematocysts.
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Phylum Cnidaria: Diagnostic Features • hydra, jellyfish, sea anemones, and corals • fresh water & marine • polymorphic (polyp & medusa forms) • benthic & planktonic • metazoans; tissue grade; diploblastic • radiate • predaceous
Histology • epidermis- epithelial muscle cells contain contractile fibers • gastrodermis- nutritive cells; flagellated; phagocytic • mesoglea- secreted, gelatinous layer between epidermis and the gastrodermis
Physiology • nervous system: "nerve net" • respiration/excretion: diffusion/ammonia • reproduction: budding; sexual reproduction in medusae; planula larvae
Classification • Class Hydrozoa • Class Scyphozoa • Class Anthozoa
Class Hydrozoa (hydroids) • diversity- 2700 species • Obelia, Gonionemus, and Hydra • Craspedacusta; found in Oklahoma; contains symbiotic algae • Physalia- Portuguese Man-O-War; colonial pelagic hydrozoan; pneumatophores
diversity- 6000 spp. most marine example: Aurelia Class Scyphozoa (true jellyfish)
Class Anthozoa (anemones & corals) • polyp form only • all marine • endosymbiotic algae
What is a coral reef? • most diverse marine ecosystems on earth • 200 million years in existence • growth ~ 1.3cm per year • calcium carbonate (CaCO3) • zooxanthellae (endosymbiotic algae)
Where are the coral reefs? • Coral reefs require clean, clear water that ranges in temperature from 24-30 OC.
Why does the coral reef need protection? • visitors are destroying the reef • touching, standing, or anchoring • boat propellers • oil
Why does the coral reef need protection? • nutrient enrichment of coastal waters • septic tank leakage • wastewater outfall • shallow injection wells • fertilizers- nitrogen and phosphorus
Phylum Ctenophora • “Comb Jellies”