Term
| Cnidarian Clades/Subkingdoms |
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Definition
Parazoa
-Sponges
- “beside the animals”
-no true tissues
Eumetazoa
-All other animals
-“true animals”
- animals with true tissues
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Term
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Definition
-Kingdom Animalia, subkingdom eumetazoa
• Most primitive Eumetazoan
• Radial symmetry
• All members have nematocytes (cnidocytes)
• specialized cells for capturing prey
• contain organelles called nematocysts (cnidocysts)
• eject barbed thread tipped with toxins
• Carnivorous
• nematocyst studded tentacles to capture prey larger
and more complex than themselves
-Stinging cells, Contain nematocyst
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Term
| Cnidarian Nematocye (Cnidocyte) Anatomy |
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Definition
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Term
| Cnidarian Specialized Cell Types |
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Definition
5 Specialized Cell Types
- nerve cells- sensory
- gland cells- ex. endodermal gland cells for digestion
- nematocytes- make toxins
- muscle cells- for movement
- interstitial cells- undifferentiated, can become any cell type
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Term
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Definition
• cells act together to perform a function
• evolutionary step above Porifera’s cellular level of
organization
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Term
| Cnidarian 2 Main Body Forms |
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Definition
sessile polyp (hydra) vs. free-swimming medusa (jellyfish)
[image] |
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Term
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Definition
ectoderm
• outer cell layer
• protective epithelium
• nerve tissue
endoderm
• inner cell layer
• lines gastrovascular cavity
mesoglea
• jelly-like layer
• between outer/inner cell layer |
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Term
| Cell Layer Anatomy of a Hydra |
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Definition
Asexual reproduction by budding
Sexual reproduction via gonads that make egg and sperm
[image] |
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Term
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Definition
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Term
| Cnidarian Gastrovascular (GV) Cavity |
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Definition
• gastro- digestive function
• vascular- circulatory function
• continuous with outside environment
• single opening is mouth and anus |
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Term
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Definition
• can eat animals larger than its individual cells
• starts extracellular
• food brought into mouth by tentacles
• gland cells secrete digestive enzymes into gastrovascular cavity
• ends intracellular
• gastroendodermal cells engulf partially digested food by
phagocytosis
• digestion completed in food vacuoles
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Term
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Definition
• excrete metabolic wastes by diffusion
• between cell layers
• out through mouth
• excrete salt into gastrovascular cavity
• regulate water balance |
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Term
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Definition
• flagellated cells circulate in GV cavity circulate
materials |
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Term
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Definition
cephalization- not much
• nerve cells scattered around mouth
• no organization or brain
nerve net cells and sensory cells
• sensitive to chemicals & touch
• coordinate muscle fiber action
• hormone glutathione produces feeding response |
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Term
| Cnidarian Life Cycle Alternates Between |
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Definition
polyp (hydra)
• tubular body with tentacles
• sessile (attaches to substrate)
• asexual form
• some species have distinct feeding and
reproductive polyps
free-swimming medusa (jellyfish)
• cup-like jelly body
• tube containing mouth hangs from center
• sexual form |
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Term
| Cnidarian: Polyp vs. Medusa (Picture #2) |
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Definition
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Term
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Definition
Asexual
• bud forms & falls off parent polyp to
become new polyp
Sexual
• medusa releases egg & sperm into
water
• fertilization in water to form zygote
• zygote develops into larva called
planula
• planula develops into polyp
• polyp develops to new medusa |
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Term
| Cnidarian Reproduction Stages |
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Definition
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Term
| Cnidarian Reproduction Diagram |
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Definition
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Term
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Definition
Anthozoa- sea anemones, most corals, sea fans, all marine
• no medusa stage
• many are colonial
• many corals have symbiotic relationship with
photosynthetic algae (dinoflagellates)
Scyphozoa- jellies, sea nettles, all marine
Cubozoa- box jellies, sea wasps, all marine
• medusa is box-shaped
• complex eyes
Hydrozoa- hydra, Portuguese man-of-war, Obelia, some corals
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Term
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Definition
• larva is ciliated and free-swimming
• adult
• polyps mostly sessile, attached to substrate
• move in place
• can detach & swim to escape predator
• medusa is free-swimming
• contractile fibers work together to coordinate movement
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Term
| Cnidarians: Symmetry, segmetation, mesoderm, type of body cavity, ciliated larva, protostome |
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Definition
Symmetry- radial; benefits sessile organism so can explore
entire environment
Segmentation- N/A
Mesoderm present- None. Only 2 embryonic cell layers
(diploblastic). Adult has epidermis (from ectoderm) and
gastrodermus (from endoderm) separated by jelly-like
mesoglea
Type of body cavity- None b/c only 2 cell layers. Need 3
cell layers to have a body cavity
Ciliated larva- Planula
Protostome- N/A
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Term
| Cnidarian cleavage, nervous system, respiratory system, digestive system, excretory system |
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Definition
Cleavage/cells- Determinant
Nervous system- None. Has nerve net. No central
control and little coordination.
Respiratory system- No complex system. Gas exchange
by diffusion through the outer and inner cell layers.
Digestive system- Gastrovascular cavity open to outside
through mouth. Digestion is extracellular using enzymes
secreted by gland cells and intracellular by flagellated cells
within food vacuoles.
Excretory system- Excrete metabolic wastes by diffusion
through the inner and outer cell layers and out through
mouth. |
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Term
| Cnidarian reproductive system, circulatory system, members, habitat and relationship to other phyla |
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Definition
Reproductive system- Asexual: regeneration and budding.
Sexual: most sessile organisms are hermaphrodites but do
get cross-fertilization.
Circulatory system- Gastrovascular cavity: water is
circulated by beating flagella to create current to bring in
oxygen and food.
Members- Hydrozoa (hydra, Obelia); Scyphozoa (jellies);
Cubuzoa (cube jellies); Anthozoa (sea anemones, corals)
Habitat- Aquatic and mostly marine. Hydra are fresh
water.
Relationship to other phyla- N/A |
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