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BIOL 202 Study Guide - Midterm Guide: Asexual Reproduction, Vacuole, Scleroprotein


Department
Biology
Course Code
BIOL 202
Professor
Laurene M Ratcliffe
Study Guide
Midterm

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Phylum Porifera (the sponges)
Symmetry
Asymmetrical (or supercially radially symmetrical)
No body symmetry
Skeletal Structure
Endoskeleton
Supported by skeleton that may consist of microscopic needlelike spikes
called spicules
oFormed by amoeboid cells
oMade of calcium carbonate or silica
Alternatively skeleton may be made of sponging
oFibrous protein made of collagen
Nonmuscular/Muscular Movement
None, sessile
Nervous System
Do not have nerve cells to coordinate body functions
Most reactions result from individual cells responding to stimulus
Other reactions do suggest some communication among cells
Sensory Organs
No sensory organs
Gas Exchange
Di#usion
oLarge volumes of water ltered so nitrogenous waste (principally
ammonia) and gas exchange occurs by di#usion)
Transport System
Di#usion (via external water)
Body forms
Feeding
Suspension feeder (a few sponges are carnivorous – deep-water, can capture
small crustaceans)
Digestion
Intracellular digestion
oOccurs within vacuole by lysosomal enzymes and pH changes
oPartially digested food is passed to amoeboid cells which distribute it to
other cells
Reproduction
Asexual reproduction (gemmules)
External fertilization
Monoecious but do usually self-fertilize
oProduce eggs and sperm at di#erent times
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