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Multicellular Heterotrophs Lack cell walls Embryology Blastula stage. Kingdom Animalia. Simple, cellular level of organization to complex Invertebrates to vertebrates Most animals (>95%) are inverts Aside from very successful insects, most animals are marine
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Multicellular Heterotrophs Lack cell walls Embryology Blastula stage Kingdom Animalia
Simple, cellular level of organization to complex Invertebrates to vertebrates Most animals (>95%) are inverts Aside from very successful insects, most animals are marine Diverse morphologies, habitats, and adaptations Animal diversity
Sponges Habitat Mostly marine, few freshwater sessile Body plan = asymmetry Suspension filter feeders Cellular level (lacks true tissues and organs) Phylum Porifera
Cells with specific functions • Porocytes: water canal • Pinacocytes: flat protective cells • Choanocytes: “collar cells” capture food (plankton) • Amebocytes: transport food; differentiate into other cells • Spicules: siliceous or calcareous skeletal structures
Diverse types & habitats Tropical to temperate encrusting Subtropical bath sponges Deep water glass sponge Reproduction Asexual budding Sexual broadcast spawn
Jellyfish, sea anemones, coral Nearly all marine Radial symmetry Two forms: medusa (swimming) and polyp Tissue level Reproduction Sexual and budding Stinging cells cnidocytes Phylum Cnidaria (nigh-dare-ia)
Tissue layer: 2 layers • Epidermis and gastrodermis • Mesoglea is middle jelly layer rather than a true tissue
Individual polyps or colonies of specialized polyps Feeding, reproductive, defense Sessile colonies Drifting colonies Class Hydrozoa
Dominant medusae stage Examples Sea Nettle Moon Jelly Upside-down Jelly Close relative Class Cubozoa Tropical Potent toxins Class Scyphozoa
Solitary or colonial polyps w/out medusae stage Sea anemones Some with zooxanthellae symbionts Photosynthesizing protists Corals CaCO3 skeletons Environmentally valuable reefs Extremely susceptible to negative impacts Pollution, increased temp., etc Class Anthozoa
Comb jellies All marine Swim with 8 rows of ciliary combs or ctenes Use tentacles with colloblasts to capture prey Adhesive, non-stinging cells Phylum Ctenophora
Flatworms Bilateral symmetry Organ level Cerebral ganglia Simple brain Reproduction: hermaphrodites Asexual and Sexual Many parasitic Phylum Platyhelminthes
Incomplete gut Three tissue layers
Similar to this mammal tapeworm example, are the marine parasitic tapeworms, “…as dense as seaweed forests, that live in the guts of sharks.”
Cestode proglottid 2 Testes Ovary Yolk gland
Ribbon worms Circulatory system Complete gut Eversible proboscis Phylum Nemertea
Roundworms All environments Marine sediments (feed on bacteria) Parasitic to most marine animals Complete gut Reproduction Always sexual One of the biggest marine parasites measures 13 meters and is two centimeters in diameter …found in the placenta of the sperm whale. Phylum Nematoda
Phylum Mollusca • Very diverse • Will discuss in more detail…
Segmented worms Earthworms Leeches Polychaetes Repetitive body parts Hydrostatic skeleton Flexibility and strength Longitudinal & circular muscles Coelomates Closed circulatory system Excretory organs Marine, moist land, and some freshwater Bilateral symmetry Some parasitic Phylum Annelida
Class Polychaeta Adaptations to predatory lifestyle Eyes, tentacles, jaws, etc Coelom Protective gut cavity Parapodia w/setae Respiratory, nervous, and locomotion Nereis