Download Unit 9 - Phylum Cnidaria – Guided Notes Introduction Body forms

Unit 9 - Phylum Cnidaria – Guided Notes
Introduction
Body forms
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_____________
o Tubular shape
o Mouth faces upwards
o Specialized for ____________________________
_________________
o Mouth faces downwards
o Motile (drifters)
o Specialized for ____________________________
Characteristics
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Most species are _________________
_________shaped or __________shaped
Ability to move at some point in life cycle
o __________________ provides swimming/somersaulting
Multicellular
o _________________________
 Epidermis – outer (from ectoderm)
 Gastrodermis – inner (from endoderm)
Middle jellylike layer – _____________________
Center of body is _________________________
_______________ surrounding the mouth
___________________________
Incomplete gut
o Mouth, no anus
o Wastes leave through the__________________
Gastrovascular cavity
o Central cavity for __________________________________________________
Respiration
o _______________________________________________
Sensory cell network – “_________________________”
o Web of interconnected nerve cells
o No ___________________________
o Can react and use tentacles to protect and bring food to mouth
Stinging Cells
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Cnidocytes: _____________________________________________________________
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Nematocysts: _______________________________
o Discharge is triggered ______________________________________________
o ________________ help anchor stinging thread into prey
o Inject _____________________into prey
o May have a direct affect or cause an immune reaction
 E.g. Box jellyfish – death in 3-20 minutes
Taxonomy
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Scyphozoa
Ex. _____________________
Cubozoa
Ex. _____________________
Anthozoa
Ex. _____________________
Hydrozoa
Ex. _____________________
Class Hydroza
 Includes __________________________
 Most live in ___________________________________in the oceans
 Ex. Physalia –_____________________________________
-___________________________, keeps colony at surface of ocean
-Tentacles up to __________ long, nematocysts poison can be fatal
Ex. Obelia -many polyps attached to branched stalks
Colonialism in Hydroids
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Live in ________________________________
Individual hydroid polyps are connected to each other by their ___________________
________________________________in the colony
o Gastrozooid: feeding polyp
 Have many tentacles for catching plankton
o Dactylozooid: defense polyp
 Use nematocysts to catch predators
Usually asexual by budding unless have:
o Gonozooid: reproductive polyp
 Produce medusoids (tiny jellyfish like)
Hydras
 Exist only as polyps, Not colonial
 Live in _________________________________________________________________
 Range from 1-4cm in length, White or brown in color
 Attach themselves to rocks or water plants by means of a sticky secretion produced by
cells in the hydra’s base
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Move by _____________________________
Reproduce asexually in warm weather –___________________________
Reproduce sexually in the fall-______________________________________________
Class Scyphozoa
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_________ animals (describes the medusa)
More then 200 species, known commonly as _______________________
______________ up to 7m long
________________________of the cup propel the jellyfish through the water
Some carry poisonous ____________________
Common jellyfish known as Aurelia
Adult medusae release sperm and eggs into water where fertilization occurs
Zygote  blastula  _________________(ciliated larva)  polyp
Class Anthozoa
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Anthozoa means “_______________________”
___________________marine species
Ex. ____________________________________________
Symbiotic relationship with clown fish
Corals are small polyps, when they die their hardened skeletons remain, over time build
up = _____________________________
Coral reefs are restricted within _______degrees north or south of the equator so
photosynthesis can occur
Phylum Ctenophora
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__________ species
“_________________” refers to the eight comb like rows of cilia that run along the
outside
Resemble jellyfish so called ____________________________
Differ from jelly fish
o Don’t pulsate through water, _______________________________
o Largest organism to move this way
o No cnidocytes instead ___________________ which secrete a sticky substance
that binds their prey
o Colloblasts normally located on __________ tentacles
o Have a sensory structure called an apical organ at one end of their body, allows it
to sense its orientation in the water
o Most striking = ________________________________________
Feeding
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The relationship between structure and function is clearly seen in the way cnidarians feed
The _____________________ capture small animals with their ________________
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The tentacles the push the prey into their _____________________________through the
mouth, enzymes found here break up the prey and cells lining the cavity absorb the
nutrients
Reproduction
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Sexual
o __________________
Asexual
o __________________
Alternation of generations
o Many cnidarians _________________between medusa and polyp forms in their
life cycle
Life cycle of Aurelia