the phylum ctenophora ktenos = comb phoros = bearing
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The Phylum Ctenophora
Ktenos = combPhoros = 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)
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
Vallicula multiformis
Coastal Ctenophores
• Order Cydippida– Round or oblong in shape– Usually less than 3 cm (1
inch) in diameter
Sea gooseberryPleurobranchia pileus
Coastal Ctenophores
• Order Lobata– Largest– Pair of lobes that are used to capture prey– Short tentacles that remain inside the lobes.
Common northern comb jellyBolinopsis infundibulum
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’ girdleCestum veneris
Tortugas red
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 (Mnemiopsis leidyi) 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?
2 layers: EndodermEctoderm with jelly-like middle called the mesoglea
Hermaphrodite
No digestive or respiratory system
Porifera: Sponges Ctenophora: Comb jellies
Asymmetrical symmetrySessileFilter feederRegenerationNo true tissues or organs
Radial symmetryMobileCarnivorousCiliaTentaclesBioluminescenceMouth/anal pores