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The Phylum Ctenophora. Ktenos = comb Phoros = bearing. How do Ctenophores differ from Sponges?. Characteristics of Ctenophora. 8 rows of combs (cilia ) Radially symmetrical Body consists of two layers with a third layer called mesoglea (jelly-like substance).
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The Phylum Ctenophora Ktenos= comb Phoros = bearing
Characteristics of Ctenophora • 8 rows of combs (cilia) • Radially symmetrical • Body consists of two layers with a third layer called mesoglea(jelly-like substance)
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
Benthic (bottom dwelling) Ctenophores • Order Platyctenida. • Found in warm water • Branched tentacles • Look more like sea slugs Valliculamultiformis
Coastal Ctenophores • Order Cydippida • Round or oblong in shape • Usually less than 3 cm (1 inch) in diameter Sea gooseberry Pleurobranchiapileus
Coastal Ctenophores • Order Lobata • Largest • Pair of lobes that are used to capture prey • Short tentacles that remain inside the lobes. Common northern comb jelly Bolinopsisinfundibulum
Coastal Ctenophores • Order Beroida • Flat and grows up to 15cm • Translucent: light pink or yellowish Beroe’s comb jelly
Oceanic Ctenophores • Found far off-shore near the surface • More fragile than coastal species • Wing-like Venus’ girdle Cestumveneris
Ctenophore life cycle • Hermaphroditic, both egg and sperm. • Eggs and sperm released and fertilized at sea. • Fertilized eggs develop into a larval stage which gradually grows into an adult.
Ctenophore life-scattering/bioluminescence: • beating rows of cilia; light defraction • Most Ctenophores are bioluminescent. Beroe
How do ctenophores fit into the food web? • All ctenophores are carnivores. • Sticky tentacles adhere to small zooplankton prey which is to the ctenophore’s mouth.
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
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
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