NABS Video?

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NABS Video?
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Lec 1b Life in Water - Adaptations
I. Diversity in Freshwater II. Adaptations to
Life in Freshwater A. Respiration B. Flow C.
Osmotic balance D. Life history E. Motion F.
Feeding Food Collection
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I. Diversity in Freshwaters
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A. Low compared to Marine (41 vs. 56 phyla 15
marine only ID?) B. Possible reasons.
1. Osmotic incompatibility 2. Ephemeral
nature of FW systems 3. Low volume 4.
Physically discontinuous -What taxa can
overcome this? (metapopn) -How do humans
help? 5. Dynamic (Chem. Phys) -actually
increases diversity. 6. Exceptions
Non-glacial lake endemics
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Insect Diversity
Ephemeroptera (Mayfly) Odonata (Dragon/Damsel) Ple
coptera (Stonefly) Hemiptera (True
Bug) Megaloptera (Hellgrammite) Trichoptera
(Caddisfly) Coleoptera (Beatle) Diptera (Fly)
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Orders of Insects with Aquatic Life Stages
Order
Aquatic Stage
Aquatic Spp
Non-Aquatic Spp
Collembola
All
25
300
Ephemeroptera
Nymphs
625
0
Odonata
Nymphs
425
0
Orthoptera
All
5
1000
Plecoptera
Nymphs
425
0
Hemiptera
All
400
4600
Neuroptera
Larvae
5
300
Megaloptera
Larvae
40
0
Coleoptera
All
1000
30000
Trichoptera
Larvae
1000
0
Lepidoptera
Larvae
50
10000
Diptera
Larvae
10?
17000
Hymenoptera
Larvae
0.5?
17000
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Fish Diversity
Fishes are the most numerous of all
vertebrates Amphibians 2500 spp Reptiles 6000
Birds 8600 Mammals 4500 Fish
25000 (Why?) Fish Distributions

• 58 are in marine (0.582500014,500spp)
• (15,482 marine species as of Nov.2004)
• 41 are in freshwater
• 1 occupy both

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II. Adaptations to Life in Freshwater A.
Respiration
Breathing air vs. water Tidal process in air,
ventilation in water Air Water Contrasts Air
Water High O2 Low O2 Light (0.013
kg/l) Heavy (1 kg/l)
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Increasing exposure to DO can be active or
passive
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Obtain O2 directly from air Snorkels
-direct rat tailed maggot -indirect use
of aquatic plants -sharp spiracles thrust into
plant arenchyma (Donacia) Tubes
Mosquitoes, Ranatra -change from caudal
tube in larvae to thoracic horns in pupae Both
make use of hydrophilic and hydrophobic
surfaces PROBLEM not transportable need
to 'grab' some air and keep it in contact w/
spiracles
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Direct diffusion through the body surface if
small (e.g. Diptera) Why not possible for
larger organisms? Tracheal gill (Ephemeroptera,
Plecoptera, Odonata, Trichoptera) -operates
best in moving water. Why? -anal gills in
Anisoptera -filamentous gills in Trichoptera,
Neuroptera -can adapt to changes in DO by
ventilation -Mayfly gills nervous and muscular
connections -Dragonflies expand and contract
rectal chamber -Damselflies fan caudal
lamellae -Stoneflies, caddisflies do 'pushups',
or undulate -Hexagenia will undulate in their
burrows to improve water flow
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Ephemeroptera (Mayflies)
Plecoptera (Stoneflies)
Questions Does the surface area of the gills
have anything to do with the DO concentration of
the habitat? What could be some mitigating
factors or adaptations?
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II. Adaptations to Life in Freshwater B. Flow
(why no/little plankton in lotic systems?)
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1. Morphology (which are general?) a. Body
flattening b. Streamlined or fusiform body c.
Reduction of projecting structures (aids
swimming) d. Anchoring devices suckers, hooks,
silk e. Small size f. Ballast 2.
Behavior a. Avoid current b. Migration (incl.
drift) c. Emergence 3. Distinct communities
(Riffle vs. pools) -Flow adapted taxa
'Rheophilic' and 'Torteniculous' taxa
Belphariceridae
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II. Adaptations to Life in Freshwater C.
Osmotic balance
One of two options.
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II. Adaptations to Life in Freshwater D. Life
History (Does the habitat meet all of the
needs for metabolism, food, reproduction?) 1.
Migration (insects, fishes) 2. Partially aquatic
(amphibians, insects) 3. Resting stages in
temporary habitats (crustaceans, molluscs)
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II. Adaptations to Life in Freshwater E.
Motion 1. Passive-Floating (Problem Most
organisms are more dense than water
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II. Adaptations to Life in Freshwater E.
Motion 1. Passive-Floating
Stokes Law - applies to very small spherical
objects
Sinking velocity of a spherical particle follows
Stokes Law g gravitational
acceleration (m / s2) ? coefficient of
viscosity of the medium (kg/m/s) densm density
of fluid densp density of particle r
radius of the particle
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Phytoplankton
Macrophytes
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II. Adaptations to Life in Freshwater E.
Motion 2. Swimming -Both push against
water and reduce drag
a. Effect of gravity is less than in air - fish
can float - leading to free movement through
a 3 dimensional environment b. Most muscle can be
devoted to movement rather than to offsetting
gravitational pull c. High density increases
resistance and hence increases energetic costs
-musculature must be devoted toward forward
movement d. Streamlining will reduce resistance
of dense water e. Surface area of 'propelling'
surface (vs. a bird better yet think about
penguin vs. flying birds)
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Jordans Rule Links between fish morphology,
water temperature, and density?

• Within species, individuals will have more
  vertebrae or body segments when reared at colder
  temps
• 2. More vertebrae in fish at higher latitudes
• 3. Water temp viscosity
• 4. How to cope? Greater flexion, more vertebrae
• 5. Check Re eqn get longer, reduce effect of
  viscosity

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Caddisfly net
F. Feeding
Blackfly larvae
Daphnia leg
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(No Transcript)
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F. Feeding
Cladoceran
Copepod
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F. Feeding
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Lab Consider some of these adaptations when
examining specimens Infer aspects of habitat and
strategies for living in water from organism
morphology