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The Phylum Ctenophora

The Phylum Ctenophora. Ktenos = comb Phoros = bearing. How do Ctenophores differ from Sponges?. Characteristics of Ctenophora. 8 rows of combs (made of cilia) Radially symmetrical Body consists of two layers with a third layer called mesoglea (jelly-like substance).

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The Phylum Ctenophora

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  1. The Phylum Ctenophora Ktenos= comb Phoros = bearing

  2. How do Ctenophores differ from Sponges?

  3. Characteristics of Ctenophora • 8 rows of combs (made of cilia) • Radially symmetrical • Body consists of two layers with a third layer called mesoglea(jelly-like substance)

  4. Characteristics of Ctenophora • Body contains an internal cavity and a mouth and anal pores • No respiratory or circulatory system; simple diffusion • Sexual Reproduction – hermaphrodites • All are carnivorous; capture prey with ten

  5. Benthic (bottom dwelling) Ctenophores • Belong to the Order Platyctenida. • Most are found in warm water; three species have been found on cold, deep sea floor. • Branched tentacles • Look more like sea slugs Valliculamultiformis

  6. Coastal Ctenophores • Order Cydippida • Round or oblong in shape • Usually less than 3 cm (1 inch) in diameter Sea gooseberry Pleurobranchiapileus

  7. Coastal Ctenophores • Order Lobata • Usually larger than cydippids • Pair of highly expandable lobes that are used to capture prey • Short tentacles that remain inside the lobes. Common northern comb jelly Bolinopsisinfundibulum

  8. Coastal Ctenophores • Order Beroida • Elongate animals that may be cylindrical or very flat; grow up to 15cm • More translucent than transparent; colorless or light pink or yellowish Beroe’s comb jelly

  9. Oceanic Ctenophores • Found far off-shore near the surface • More fragile than coastal species • Wing-like Venus’ girdle Cestumveneris

  10. Tortugas red

  11. Ctenophore life cycle • Ctenophores are hermaphroditic, both egg and sperm. • Spawn eggs and sperm freely in the sea where sperm finds the egg and fertilizes it. • Fertilized eggs develop into a larval stage which gradually grows into an adult.

  12. Ctenophore life-scattering/bioluminescence: • Light-scattering is produced by the beating rows of locomatory cilia; light defraction • Most Ctenophores are bioluminescent. Beroe

  13. How do ctenophores fit into the food web? • All ctenophores are carnivores. • Sticky tentacles adhere to small zooplankton prey which is brought across the ctenophore’s mouth.

  14. Ctenophores as marine invaders wreaking ecosystems: • Ctenophores are recognized to be planktonic carnivores • Leidy’s comb jelly (Mnemiopsisleidyi) was introduced into the Black sea and caused a full ecosystem fisheries collapse within less than 10 years • Why? • Outcompeted for plankton Order Lobate

  15. Ctenophores and Medusae (Jellyfish) are they related? • No • Both are plank tonic, carnivorous, often transparent and tentacle bearing • At one time, they were both placed in Phylum Coelenterata but today they are separated. • No polyp stage in Ctenophores

  16. How are Phyla Porifera and Ctenophora similar? Different? Porifera: Sponges Ctenophora: Comb jellies 2 layers: Endoderm Ectoderm with jelly-like middle called the mesoglea Hermaphrodite No digestive or respiratory system Radial symmetry Mobile Carnivorous Cilia Tentacles Bioluminescence Mouth/anal pores Asymmetrical symmetry Sessile Filter feeder Regeneration No true tissues or organs

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