Survey of Aquatic Invertebrates

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Survey of Aquatic Invertebrates

• Lifestyles
• of the
• Spineless and Gilled

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Phylum Porifera the Sponges
                                                
                        ltgt

• Asymmetrical
• Sessile - attached to submerged rocks, sticks,
  logs, or aquatic vegetation
• Vary from marble-sized to elongated masses and
  can grow to be thin or thick encrusting layers.
• Their structure is supported by spicules, tiny
  needle-like structures made of silicon that are
  distributed throughout the sponge body.
• Sensitive indicators of pollution.
• Filter feeders
• Little is known about them!

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Phylum Cnidaria, Class Hydrozoa the Hydra

• Radial Symmetry
• Carnivorous, kill with nematocysts (stinging
  cells)
• Somewhat sensitive to pollution
• May reproduce sexually or
• asexually

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Phylum Platyhelminthesthe Flatworms

• Bilateral Symmetry
• Have 3 layers
• lack coelom, anus, circulatory and respiratory
  systems
• Very tolerant of pollution

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Phylum Annelidathe Segmented Roundworms

• have external segments
• that correspond with
• repeated digestive and
• reproductive organs.
• include leeches,
• aquatic earthworms, tubifex worms and bristle
  worms
• Very tolerant of pollution
• Hermaphroditic reproduce
• sexually by means of exchange of
• gametes

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Phylum Mollusca

• Bilateral Symmetry
• Specialized Foot
• Mantle
• Radula
• 2 Aquatic Classes
• Pelecypoda (Bivalvia clams, mussels)
• Gastropoda (snails)

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Freshwater Bivalves
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Freshwater Bivalves Life History

• Freshwater mussels feed by filtering algae and
  small particles from the water.
• Most are somewhat sensitive to pollution.
• Most species have a larval stage that is
  parasitic on fish.
• Larvae are released by the female mussel and must
  locate a certain fish species or die.
• They usually attach to the host fish's gills or
  fins where they remain for a few weeks or months.
  
• Larval mussels rarely harm infected fish under
  natural conditions.
• If essential fish species are removed from the
  habitat, mussels will not be able to reproduce.

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Freshwater Bivalves their life cycle
illustrated
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Bivalves can tell us alot about history!
http//www.texasbeyondhistory.net/jbwhite/musselma
nia/flash.html
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Class Gastropoda the Snails

• May be carnivorous or herbivorous.
• Hermaphroditic
• Most are highly tolerant of pollution.
• May or may not possess an operculum, or lid
  that it can close its shell with.
• When looking at the shells opening with the
  narrow end up, the opening may be on the right of
  the spiral (dextral) or to the left (sinistral)

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Class Gastropoda the Snails

• Planorbid Snails coiled flat, no operculum
• Lymnaeid Snails dextral, no operculum
• Physid Snails sinistral, no operculum

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Bithynid Snail
Dextral stiff operculum, with well-centered
concentric rings
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Viviparid Snail
Dextral flexible operculum, with off-center
concentric rings.
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Hydrobiid Snail
Dextral has flexible operculum with multispiral
rings
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Pleurocerid Snail
Dextral very flexible operculum that recedes
deep into shell, paucispiral rings
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Planorbid Snail
Coiled flat, no operculum
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Lymnaeid Snail
Dextral, no operculum
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Physid Snails
sinistral, no operculum
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Phylum Arthropoda

• Bilateral Symmetry
• Jointed Appendages
• Exoskeleton of chitin
• Most important aquatic groups
• Arachnida Crustacea
  Insecta
• (very tolerant) (somewhat tolerant)
  (variable tolerance)
• Water Mites Scuds
  Water Bugs (tolerant)
• Water Spiders Isopods
  Water Beetles (sensitive)
• Seed Shrimp
  Odonate nymphs (varies)
• Grass Shrimp
  Plecoptera nymphs
• Crayfish
  (extremely sensitive)
• 
  Ephemeroptera nymphs
  
  (extremely sensitive)
• 
  Megaloptera nymphs (sensitive)
• 
  Diptera larvae (very
  tolerant)

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Phylum Chordata

• Bilateral symmetry
• Possess notochord, chambered heart, closed
  circulatory system
• Includes vertebrates.
• Some quasi-vertebrate examples
• Lampreys
• Tadpoles

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Lampreys
No paired fins, no jaws. Gill slits, cartilage
skeleton Our native Southern Brook Lamprey
(Ichthyomyzon gagei, pictured) has a larval stage
that is a detritivore adults are ephemeral, do
not eat.
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Tadpoles
Bufo valliceps Gulf Coast Toad
Rana sphenocephala Southern Leopard Frog
Rana catesbiana Bullfrog
All larval amphibians are very primitive in that
they lack jaws, paired fins. All are Detritivore
until they get hind legs, and jaws, then become
predaceous.
Rana clamitans Bronze Frog
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http//www.bgsd.k12.wa.us/hml/jr_cam/macros/amc/in
dex.html
http//www.ncsu.edu/sciencejunction/depot/experime
nts/water/tutorial/tutorialmacro.html
http//rock.geo.csuohio.edu/norp/bmi.htm
http//www.cod.edu/people/faculty/chenpe/RiverWatc
h/MBI_calculator.html