Download Cnidarians - Parma City School District

Cnidarians
(Coelenterates)
Phylum Cnidaria (Coelenterata)
• Class Hydrozoa = Hydra
• POLYP body form = “vase shaped” ; sessile
• Most live in colonies.
1 of 3 classes within Phylum
Cnidaria
Phylum Cnidaria (Coelenterata)
• Class Scyphozoa: “Cup Animals”
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Medusa body form (bell-shaped); swimming
Commonly known as jellyfish
“Portuguese Man-o-war”
200 different species
Phylum Cnidaria (Coelenterata)
• Class Anthozoa: “Flower Animals”
– 6,100 different species
– Sea Anemones, Corals
– Coral Reef = 30 degrees North or South of the
equator, shallow water for photosynthetic algae
that live in symbiosis with coral
Classification
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Common Name: Hydra
Scientific Name: Hydra
Phylum: Cnidaria
Class: Hydrozoa
Other: Phylum Coelenterata (Old name)
Major Characteristics
• Body Plan: Hollow, 2 layered sac
• Body Cavity: Endoderm, Mesoglea (jelly
like), Ectoderm
• Symmetry: Radial - pull in food from all
around
• Cell Specialization: No Organs,
Nematocysts = harpoon like stinging cells;
neurotoxins cause paralysis
Life Support Processes
• Absorption: Gastroderm; directly into the
body wall
• Feeding: tentacles pull food into the
mouth; they are carnivores
• Digestion: Gastroderm (endoderm), food
vacuoles in cells
• Respiration & Circulation:
Gastrovascular inner cavity
Life Support Processes
• Excretion: Mouth opening, diffusion
• Secretion: sticky base for attachment
• Response: Nerve Net - contractile fibers in
the epidermis; Ocelli - detects light
• Movement: contractile fibers; tumble
motion through the water
• Reproduction: Asexual = budding; sexual
= hermaphrodite (no self fertilization)
Life Support Processes
• Support: tissue layers, hydroskeleton
Ecological Relationships
• Freshwater living
• Solitary - not colonial like most hydrozoans
• Carnivorous - predatory lifestyle
Body Systems Compared With
Humans
• Tissues - layers like our skin
Advancements Over the Previous
Phylum
• Nervous Structure
• Movement
• Active Feeding
Diagram of Hydra
• The largest jellyfish is the Arctic Giant
Jellyfish: it can have a diameter over 8 ft.
with tentacles stretching as long as 120 ft.
• The most venomous jellyfish is the
Australian Sea Wasp; death can occur
within 1-3 minutes.
• The Great Barrier Reef is the worlds
largest stony coral structure stretching for
1,260 miles off Northeast Australia.
Lion’s Mane
Jellyfish
Preventing beach erosion
Coral Reefs can be
visible from the
air!
Great Barrier Reef - Australia