BIOL 322 Flashcards
What suspension feeders consume
- phytoplankton
- zooplankton
- bacterioplankton
- POM
suspension feeding unique
-almost entirely unique to aquatic environment
some spiders suspension feed pollen
organisms who spend entire life in the plankton
holoplankton
plankton sizes
picoplankton 0.2-2um nanoplankton 2-20um microplankton 20-200um mesoplankton 0.2-20 mm macroplankton 2-20 cm
filter feeding
a type of suspension feeding
the goal of suspension feeding
to capture and ingest very small particles from a very large volume of fluid
Suspension feeding steps
- water transport
- particle capture
- transport particles to mouth
- ingestion
organisms who spend one component of their life history in the plankton
meroplankton
Net Gain (E) =
consumed - costs
Consumed =
quality x quality
Reynolds number
- relative importance of viscous to inertial forces
- determines physical characteristics of fluid flow around object
Reynolds number =
(velocity x object size x density) / viscosity
flow vs velocity
low velocity = laminar flow
high velocity = turbulent flow
laminar flow reynolds number
less than 10
increased velocity (Re #)
= increased Re #
= inertial forces > viscous forces
= turbulence
= smaller boundary layer
boundary layer
‘coating’ of water that is not flowing
turbulent flow reynolds number
above 200,000
barnacle cirri
biramous, cetose
- appendages
- long axis = ramus
- branches = citi
ways to induce passive water flow
- Bernoulli’s principle
- Dynamic pressure
- Viscous entrainment
what is inducing passive water flow
-organisms exploiting flow of water to augment role of water flow through body
Bernoulli’s principle
inverse relationship between fluid speed and pressure
Bernoulli’s principle in the ocean
- water mass in contact with ocean floor is slowed due to drag = high pressure
- water masses above ocean floor successively faster = lower pressure
exploiting Bernoulli’s principle in the ocean
- fluids flow from high to low P
- raise body parts to lower P areas and water will naturally flow over them
sponge parts
ostia - holes in sides of body that water flows in
osculum - hole in top that water flows out
choanocytes - flagellated cells that line the interior and induce water flow
what is viscous entrainment
-water molecules are adhesive due to H-bonds
taking advantage of viscous entrainment
utilize adhesion to ‘pull’ water out of chimney
dynamic pressure
kinetic energy of a fluid
Dynamic Pressure/ Viscous entrainment example
Styela montereyensis, stalked tunicate
- elaborate long flexible stalk
- in high flow: recurved buccal siphon
- stalk bent over in high flow, water forced into opening
stalked tunicate experiment
- free to move or forced in upright position by mesh bag
- free to feed for 24hr
- clean water, catch excretions
- free to move organisms had higher excretions, fed more, therefore had more water move through body
exploit active and passive feeding
acorn barnacle
-active in low flow, rake cirri through water to reduce boundary layer
porcelain crab
-rake 3rd pair maxilliped through water
Balanus phenotypic plasticity
- log ramus length decreases linearly with water velocity
- shorter in high velocity
Advantage of short legs in high velocity (barnacle)
more robust to wave damage
Madracis mirabilis
- scleractinian colonial coral w/ branched fingers
- in low flow polyps on opposite side of flow trouble feeding
- high flow polyps on opposite side can feed (turbulence), others are flattened
how to tell that which coral polyps are feeding
- in flume with unidirectional water
- feed brine shrimp cysts (dark brown) can see them inside polyp
Spinoid marine annelid
facultative suspension feeder
- tube in sand/mud
- lay palps on ground, cilia pick up particles (deposit feeding)
- if current velocity increases, raise palps and coil
Advantage of long legs in low water velocity (barnacle)
- more surface area
- Bernoulli’s principle
Why does Spionid coil palps
- increase length of palp that is normal to flow
- larger diameter relative to straight palp, increase Re
particle flux
of particles that move past point during any period of time
Spionid experiment
- start: high particle flux, suspension feeding
- add filter, water v same
- less suspension feeders
- remove filter, more suspension feeders
what does Spionid experiment show
- they are not suspension feeding b/c of water velocity
- changing feeding mode to do particle flux
- coincides w/ water v b/c low v allows particles to settle, high entrains them
Particle Capture Mechanisms
- filtering
- scan and trap
- direct interception
- ciliary mechanisms
filter feeding
- device meant to have water flow through
- particles larger than mesh/pore size are retained
scan and trap feeding
isolate parcel of fluid containing food particle
scan and trapper
copepod
- swim on back
- detect particle
- fling open 2nd maxillae – change Re
- suck particle in
- fling maxillae shut
- expel water
direct interception
surface of capture device is adhesive
filter feeding examples
barnacle
porcelain crab
direct interception example
Daphnia
-feeding combs (setae and setules)
-surface charge adheres to small particles
Brittle Star
-sticky tube feet, mucous net extended between tube feet
Ciliary feeding
- bivalve ctenidia
- long lateral cilia pass food to food groove
reef-forming suspension feeders
- corals, oysters, mussels, tube worms
- usually sessile
- usually large aggregations
- ecosystem engineers
reef ecosystem services
- Habitat complexity
- pelago-benthic nutrient cycling
- water clarity
- Mixing of dissolved gases
habitat complexity (reefs)
- increased settlement surface
- increased biodiversity
- niche space
- hiding space
nutrient cycling (reefs)
- ingest PP
- bring E into benthos
- couple energy and nutrients btw water column and benthos
Benthic boundary layer
-benthic suspension feeders need downwelling mechanism to get particles
getting past benthic boundary layer
- flow-generated mixing
2. biomixing
flow-generated mixing
- surface irregularities generate turbulence
- highest turbulance at greater flow speed
biomixing
- exhalent jets create vortices
- most helpful at low current speed
reef restoration experiment
- often fail
- test if threshold reef height is critical determinant of self-sustaining
plankton
- small organisms (up to 10cm)
- live in water column
- cannot swim against current
example of passive suspension feeders
- hydroids
- corals
- crinoids
- brittle stars
- sea cucumbers
streamline
viscous forces keep fluid together and flowing in smooth lines
inertial forces
break fluid up into uneven streamlines
active suspension feeders, examples
- lamellibranch bivalves
- sponges
- ascidians
- bryozoans
- polychaetes
reef height and restoration effort experiment
- build experimental reef of empty shells of various heights
- “blocks” on sides
oyster reef experiment results
higher reefs have less sedimentation
-0.3-0.4m threshold for success (at this site)
reefs and sedimentation
- sedimentation reduces rugosity
- turbulance reduces sedimentation
DOM
- does not settle out of fluid over time
- very heterogeneous in distribution and compilation
- lots of organic carbon
DOM abundance
30-100 umol/kg
organic carbon in biosphere
plant biomass ca. 800x10^9
dissolved in seawater 1600x10^9
primary DOM source
phytoplankton
measuring rugosity
- drape fine link chain over
- measure length of chain needed from one side to the other
Is DOM utilized by organisms
- first proposed in 1906 (August Putter)
- measured in 1950s (Grover Stephens)
measure uptake of DOM
- high [ ] inside organism
- particles must move against steep [ ] gradient
- measure movement w/ radioisotopes (C14)
- must make sure organism taking up DOM not bacteria (add antibiotics)
HPLC
high pressure liquid chromatography
- measures very very small amounts of a product
- molecules percolate through cylinder of beads
DOM uptake
- not linear with [ ]
- saturates
- indicative of enzyme
- Na dependent co-transporter
Na dependent co-transporter
- Na continually pumped out of cell
- Na constantly diffuses back in
- co-transporter has binding sites for Na + 1 other molecule
- Na movement coupled
- depends on Na/K pump (and ATP) to create this gradient
does DOM make significant contribution to nutrition
- measure larvae uptake
- quantify E in yolk
- find larvae burn more E than available in yolk (yolk = 71%)
DOM uptake example
Parastichopus californicus
- seasonal atrophy of gut
- reduce metabolic rate in times of low nutirents
- where does E come from to rebuild gut?
- find increased isotope [ ] in respiratory tree
holobiont
host + all microorganisms present
coral reefs
- 1/4 of marine biodiversity
- mostly in nutrient poor waters
symbiont hosts
- cnidarians
- molluscs
- turbellarians
- acoels
- poriferans
- protozoans
“algae”
- unicellular photosynthetic organisms
- dinoflagellates (zooxanthellae)
- chlorophytes (zoochlorellae)
- cyanobacteria
symbiodinium
- 9 clades (A-I), subclades
- each w/ unique tolerances
- once thought to be one species
symbiont location
intracellular vacuole in gastrodermal cells = symbiosome
acquisition of symbionts
- asexual reproduction
- sexual reproduction
- horizontal transmission
sexual reproduction, symbionts
- vertical (maternal) transmission
- 15% of acquisitions
- mother places symbionts in egg
horizontal transmission, symbionts
- newly acquired by each generation
- 85% of acquisitions
symbiont host benefit
-obtain 90% of symbionts photosynthate
-promote calcification rates
-
demonstration of translocation of photosynthate to host
- sodium bicarbonate w/ radioisotope
- NaH14CO3 -> Na+ + H14CO3-
- H14CO3- -> H2O + 14CO2
- find 14C in animal tissue, animals can’t fix C
Symbiont benefit
- require carbon concentrating mechanism
- N source
carbon concentrating mechanism
host membrane-bound proton pump
why does host need carbon concentrating mechanism
- CO2 from host respiration is not enough
- CO2 is limiting in aquatic environment
- CO2 dissolves and forms bicarbonate, charged molecule can’t pass through membranes
CO2 in seawater
CO2 + H2O –> H+ + HCO3-
membrane-bound proton pump
- ATPase
- pumps H+ out
- H+ combines w/ bicarbonate to turn back into CO2
- Carbonic anhydrase (CA) catalyzes reaction
- may occur at every membrane (4)
symbiont N
- assimilate host’s ammonia
- host anthozoans import nitrate from SW (unusual)
- 3rd partner: N-fixing cyano.
truly beneficial for symbiont?
- zooxanthellae double every 3days in culture, every 70-100 days in symbiosis
- host may regulate symbionts N access
cost to host
- UV exposure
- ROS
PAR
photosynthetically active radiation
full spectrum sunlight
PAR + UVR (UVA and UVB)
UVA and UVB
UVA: 400-320nm
UVB: 320-280nm
-B more damaging
UV damage
- damages DNA, protein, lipids
- creates ROS
UV protection
- sunscreen
- antioxidants
- photoactivated DNA repair enzymes
Sunscreen
- MAA
- animals can not produce
- different types, unique max abs.
- more MAAs = broad spectrum protection
MAA
mycosporine-like amino acids -cyclohexane ring -conjugated to amino acid or amino alcohol Shikimate pathway -plants, bacteria, fungae
primary MAA
- synthesized by dinoflagellate
- short half life
- can be upregulated by UV light
- not a lot of types
secondary MAA
- modified primaries
- longer half life
- broader coverage for host and symbiont
- not up-regulated
ROS
reactive oxygen species
ROS generated by
- photochemical reactions of photosynthesis
- hyperoxia
hyperoxia
- pure oxygen damaging in excess
- electron loss = O2^- = superoxide radical
- scavenges electrons = oxidative damage
normoxia
150 mmHg
light energy pathways in organism
- photochemistry = ROS
- Fluorescence
- Heat dissipation
- Chl reaction = ROS
ROS solution
superoxide dismutase
-detoxifies ROS
detoxify ROS
O2^- + H+ – w/ superoxide dismutase –> H2O2 + O2
catlase
breakdown H2O2
2H2O2 –catalase –> 2H2O + O2
what happens to photosynthate
90% translocated to coral
-40% of that released in mucus
coral mucus
Insoluble: upwells, particle trap, concentrates particles, descends, enriched
soluble: DOM, bacteria substrate
Coral bleaching, symbiont loss hypotheses
- adaptive bleaching hypothesis
- host differential tolerance hypothesis
- response to ROS damage
coral bleaching, stresses
- thinning of ozone – increased UV
- pollutants, eutrophication
- ocean acidification
- global warming ***
DHW
degrees heating weeks
- combines increased T and duration of exposure
- number of º above average for each week
adaptive bleaching hypothesis
- expel symbiont to get a more suitable one
- presumes clade surviving in water is better adapted to stress
Chiriqui Panama corals
2 bays, one exposed to higher T variations
-switch from more of C clade to all D during ENSO and then regain some C after
why switch to D clade
- D more resistant to high T
- C more efficient
Host differential tolerance hypothesis
-corals differ in physiological capacity to withstand high T
evidence of host differential tolerance hypothesis
- fore reef vs back reef corals in Indo-Pacific
- back reef high variability, fore reef moderate variability
- no difference in C:D clade ratio
Transplanted Indo-Pacific corals
- transplanted corals adapted to their surrounding, HV lost their tolerance in MV
- evidence of acclimation
- no change in proportion of C:D
Response to ROS damage
- current hypothesis
- elevated T’s cause severe oxidative stress-
- bleaching is a collapse of the delicate balance of the partnership
- symbiont becomes toxic to host b/c host can no longer tolerate ROS
Siboglinidae
- hot vent tube worms
- trophosome derived from gut tissue (no gut)
- bacteriocyte cells contain H2S oxidizing bacteria
sign of CB cycle occurring
RuBisCo
evidence of bacterial metabolism in vent worm
- S in trophosome
- TEM: trophosomal cells packed w/ bacteria
- assay for sulfide oxidation enzymes (benzyl viologen)
- assay for RuBisCo
- sulfide stimulation of 14CO2 fixation
Solemya readi
- gutless bivalve
- under logging boom, burrow in anoxic sed.
- sulfide oxidizing bacteria in gills (thiotrophic)
- large foot to pull in H2S from sed.
gutless oligochaete
- bacteria btw cuticle and epihelium
- vertical transmission (mother)
- sulfide defense, nourishment
sulfide toxicity
metabolic toxin
- binds to cytochrome oxidase
- shuts down electron transport
Defense against sulfide toxicity
- switch to anaerobiosis temporarily (less E)
- external coating of sulfide-oxidizing bacteria
- sulfide-binding hemoglobin
- sulfide-binding proteins
- partial oxidation of slide in mitochondria
methanotrophic bacteria ex
bathymodiolus
- mussels fueled by gas
- methanotrophic bacteria in gills
- thiotrophic bacteria
thioautotrophic bacteria
- E source = H2S
- C source = CO2
methanotrophic bacteria
E source = CH4
C source = CH4
mwethanotroph methane oxidation
CH4 – CH3OH – CH2O – CHOOH – CO2
Methane – methanol – formaldehyde – formic acid – carbon dioxide
Osedax
bone-eating worms
-contain heterotrophic bacteria in roots that produce enzymes that can degrade organic substrates within bones
Xylotrophic
‘wood eating’
- shipworm symbiont
- cellulose/lignin E and C source
- capable of N fixation
shipworm
- wood boring bivalve
- 2 clades
teredo worm
shipworm
- elongate, worm-shaped body
- shell valves specialized as cutting tools
- line burrow w/ calcareous coating
Skeleton functions
- protect
- support
- maintain shape
- facilitate movement
- anchorage
skeletons perform their functions by
accommodating forces
accommodating forces
- resist force
- transmit force
- store energy of forces
types of forces
tension
compression
shear
how skeletal elements accommodate force depends on
- shape
- material properties
tension examples
- ropes
- byssal threads
- tendons
- spider webs
- tentacles
sheets (forces)
- accomodate tension in all directions
- good for distributed loads
- not good for point loads
- ex. bat wing
invertebrate skeletal sheet examples
- medusa bell
- beetle elytra
- chiton shell plates
3D skeletal structure
- solid beam
- hollow cylinder
- sponge column
coarse skeletal material classification
- Rigid: stiff, solid
- Pliant: flexible solid
- Hydrostatic: fluid, constant volume
precise skeletal material classifications
- strength
- extensibility
- stiffness
- toughness
- Resilience
extensibility
-how much does material extend when it reaches its breaking stress
Young’s modulus
= stiffness
- slope of stress-strain curve
- measure of ability of a material to withstand changes in length when under lengthwise tension or compression
high Young’s modulus
= high stiffness
-needs more force to deform
toughness
- work to extend
- area under the stress-strain plot’
- ability of material to absorb E and deform without fracturing
strength
ability to withstand load without plastic deformation
resilience
ability of material to absorb E when deformed and release upon unloading
Material properties of skeletons important points
- Animals typically have many different types of skeletal components
- Skeletal components are often composites of multiple materials
- Material properties of composites can be complex
example of Animals typically have many different types of skeletal components
sea urchin
- biomineralized endoskeleton
- connective tissue
- hydrostats
example of Skeletal components are often composites of multiple materials
mollusc shell is a composite of protein and mineral
Material properties of composites can be complex
stress-strain curve may not be linear
muscles
- shortening machine
- apply tension
- tensile force transmitted through rigid skeletal element or incompressible fluid at constant V
muscle performance parameters
- speed of shortening
- maximum tension
- effective length range
- twitch frequency
- endurance
flicking of crab attendees (muscle)
- high shortening speed
- low max tension
- short length range
- high twitch freq.
- high endurance
burrowing bivalve adductor muscles
- high max tension
- slow shortening speed
- short working range
- very low twitch frequency
- very high endurance
differences in muscle performance facilitated by
- contractile component
- control component
- energy-supplying component
contractile component of invert muscles
- speed of shortening
- maximum tension
- effective length range
muscle structure
- actin myofilament
- myosin myofilament
- arranged in sarcomeres
- between z disc
thick filament
myosin
sarcomere
- myosin filaments arranged inside of acting filaments
- minus ends of actin at midline
- plus ends of actin end on z disc
control component of invert muscle
- twitch duration/frequency
differences in muscle performance facilitated by
- contractile component
- control component
- energy-supplying component
velocity
n(dx/dt)
thin filament
actin
energy-supplying component of invert. muscle
endurance
distance
nx
higher n in series = greater distance and velocity
contractile units in parallel
force = nf
- higher n = greater force
- does not impact distance or velocity
contractile component and speed of shortening
- dephosphorylation rate for myosin ATPase
- number of sarcomeres connected in series
muscles with short sarcomeres
generates rapid shortening
contractile component maximum tension
- number of muscle filaments/fibres connected in parallel
- length of myofilaments
high maximum tension =
long sarcomeres
lobster chelipeds
major crusher
minor cutter
lobster cheliped sarcomeres
- crusher: lots of long sarcomeres
- cutter: bimodal, mostly short sarcomeres
why long fibres
maximize surface tension
myofilament arrangements
- cross straited
- obliquely striated
- smooth muscles
smooth muscle
- extremely long myofilaments
- extremely large length range
- very high max tension
cross striated muscle
- z discs perpendicular to muscle fibre
- not common in inverts
obliquely striated
- z discs angled relative to fibres
- contractile units realigned
- large effective working range
most invertebrate muscles are
smooth
-soft highly extensible bodies
smooth muscle
- myosin filaments very very long
- very long working distance
- maximize sites for A&M binding
- highest max tension
- powerful but not rapid contraction
swimming scallop
- mixed muscle w/ smooth and striated to exploit speed and strength
- less strong than other bivalves
sarcoplasmic reticulum
smooth endoplasmic reticulum
-regulates [Ca] in cytoplasm of striated muscle cell
myofibril
linear array of sarcomeres
sarcoplasm
cytoplasm of muscle
Ca++ release from SER to sarcoplasm
-exposes myosin binding sites on actin filaments
If Ca++ is important for A/M binding but Ca is immediately re-sequestered, how to reduce timing
shorten distance
- increase amount of SER
- twitch duration highest for high $ of myofibril occupied by SR
to flick antenules rapidly
short sarcomere
to flick antenule AGAIN rapidly
high density SR
muscle energy supply
- Mitochondria
- Energy storage molecules
- Anaerobic (glycolosis)
Burst Activity energy supply
Energy storage molecules
energy storage molecules
phophocreatine
phosphoarginine
high endurance muscle
mitochondria
aerobic
continual ATP supply
squid mantle
- continuous contractions to hydrate ctenidia
- rapid contraction escape behaviour
- Peripheral zone (PZ) high citrate synthase
- Medial zone (MZ) high phosphoarginine kinase
phophoarginine kinase
Energy storage molecule
-rapid bursts
Citrate synthase
- oxidative metabolism
- endurance muscles
bivalve catch muscle
- maintain adductor muscle shortening for very long time w/ minimal E expenditure
- thick filament
- twitchin protein
twitchin catch
- acetylcholine released by nerves
- depolarization of sarcolemma
- release of Ca++ from SR
- myosin moves along actin
- muscle shortens
- Ca++ moves back to SR
- decrease [Ca]
- twitchin conformational change
- twitchin binds A/M complex
- AMT complex can not slide back to start
sarcolemma
muscle membrane
twitchin release
- serotonin released from neuron
- release cAMP
- activate cAMP dependent protein kinase
- phosphorolate twitchin
- conformational change
- release A/M complex
why is animal size important
- influence available food options
- influence susceptibility to predators
- influences SA:V
power function equation
y = ax^b
quantifies relationship btw any 2 dimensions as size increases
b in power function
scaling exponent
to determine scaling coefficient
logarithmic conversion
log y = log a + b log x
predicted scaling coefficients under hypothesis of isometry
length and length: b = 1
area, length: b = 2
volume, length: b = 3
volume, area: b = 3/2
SA, V of a cume
SA = 6L^2 V = L^3
isometry
geometric similarity
- different size
- same shape
allometry
not geometrically similar
- different size
- different shape
If scaling coefficient falls within CI
allometric
arthropod appendage segment
article/podomere
musculoskeletal lever components
- stiff beam (solid or hollow)
- joint (fulcrum)
- muscle attachment
high flexural stiffness
resistance to tension and compression
flexural stiffness =
E x I
E = material stiffness
I = second moment of area
second moment of area
sum of all distance of all particles away from plane of neutrality
why a solid beam is not significantly stiffer than hollow
middle ‘stuff’ close to plane of neutrality, doesn’t contribute much to I
-good news for arthropods
best way to increase FS
increase diameter just a little
-more points, farther from the plane
force on under side of beam bent down
compression
I varies as
r^4
second moment of area and therefore flexural stiffness highly dependent on radius
I beam
maximize material on compression/tension side of beam
force on upper side of beam bent down
tension
Joint morphology
- determines range of movement
- condyles
- less cross-linking of exoskeleton
condyles
- joint fulcrum
- unidirectional movement
- complimentary condyles at end of article
- attach to antagonistic muscles via apodeme
Apodeme
internal projection of exoskeleton
- poorly cross linked
- flexible
- cartiladge like
- analgous to vertebrate tendons
musculoskeletal lever system mechanical advantage
- speed vs. force amplification
- compare lever arms
input lever arm
from fulcrum to where the force is applied
Li/Lo greater than 1
- force lever larger than load lever
- maximize force
arthropod limbs amplify speed or force
distance/speed advantage
why arthropod limbs have distance/speed advantage
- fast running
- swimming
- increased Re
output lever arm
from fulcrum to load
what about when arthropods need force
- large thing apodeme sheet
- pinnate muscles amplify force
Li/Lo less than 1
- short force lever
- maximize speed/distance
why large apodeme
more sites for muscle attachment
pinnate muscle
- angled, v-shape attachment to apomere
- less stretch area required
- much much greater force
- take up much less room
Snapping shrimp
- high force AND speed
- 1 enormous cheliped
how snapping shrimp snaps
- ‘slot’ in propodus filled with water
- dactyl plunger inserted with high speed and force
- water expelled rapidly
- P drop below Pair in water (bernoulli)
- air forms cavitation bubble
- bubble collapses
- pressure wave
why does snapping shrimp create pressure waves?
stun prey
how does snapping shrimp achieve speed and force
Ballistic device
- pre-load spring with potential E
- abruptly release load
snapping shrimp spring
open dactyl – apodeme attachment point moves above pivot pt – closer muscle 1 contracts – any further tension in Cl1 loads the spring
snapping shrimp spring snapping
Cl2 contracts — pulls dactyl closed a small amount – attach pt moves below pivot pt – built up tension is released
another name for uptake of DOM
integumental nutrient transport
non-integumental nutrient transport
intestinal nutrient transport
typical [DOM] in temperate coastal marine water
30-100 umol/kg
most common methods using radioisotopes in biology
- scintillation spectroscopy
- autoradiography
scintillation spectroscopy
- E released by radioisotopes in solution is absorbed by fluorophores
- fluorophores emit absorbed E as light
autoradiography
- radioisotopes in tissue detected with photographic emulsion
- E released by decay reduces Ag grains in photographic emulsion
what problem did HPLC solve in terms of DOM uptake
capable of measuring NET flux
-show that DOM influx ≠ efflux
combustion constant
amount of energy released by a unit quantity of organic substrate
criticism of DOM larval experiment
-wholly dependent on accuracy of analytical measurements
a better DOM experiment
measure performance or survival in presence or absence of DOM
animals
heterotrophic eukaryotes
phyla of animals that host algal symbionts
at least
- Porifera
- Cnidaria
- Aceolomorpha
- Platyhelminthes
- Mollusca
endosymbiont
intracellular
animal-algal symbiosis in fresh water
mostly zoochlorellae
algal cells in animal hosts are located within
symbiosomes
membrane-line intracellular vacuoles
eggs do not have symbionts, juvenile must acquire them
horizontal transmission
more common
most common form photosynthate is translocated in
glycerol
If symbiosis is important in tropics due to low nutrients, what is the importance in temperate zones
possibly due to time spent out of water
-ex. anemones spend up to 30% out of water
signature enzyme of the Calvin-Benson cycle
Rubisco
Calvin-Benson cycle
metabolic pathway that incorporates CO2 C atom into organic carbon
molecular oxygen that has lost an electron
superoxide radical
shorter wavelength =
higher energy
why tropical corals are at higher risk of UV
- UV intensity higher at lower lats.
- less DOM to quench/reflect UV = greater penetration
how the coral host is able to maintain a symbiont
-suppression of the host’s innate immune system
if host innate immune system not suppressed
recognize symbiont as foreign tissue – expelled or destroyed
–pathological response, not adaptive
animal - prokaryote symbiosis example
- blood feeding arthropods for B vitamin
- cows for cellulose degradation
vent worms discovered
- 1977
- Woods Hole
- Alvin
tubeworm tentacles
branchial filaments
-high [hemoglobin]
what does elemental sulu in the trophosome suggest
oxidization
-oxidized form of sulfide
how to measure sulfide oxidation in absence of oxygen
benzyl viologen
- e acceptor
- converts colourless compounds to purple
specialized ctenidia epithelial cells that contain intracellular bacterial symbionts
bacteriocytes
sulfide oxidizing bacteria
thiotrophic
wood eating
xylophagy
digesting cellulose often requires
-symbiotic cellulolytic bacteria
shipworm tunnel cover
pallet
xylotrophic bacteria where in shipworms
bacteriocytes in the ctenidia
why are shipworms of interest to biofuel industry
cellololytic bacteria provide second order biofuel
ability of a beam to resist bending
flexural stiffness
material stiffness
- slope of the stress-strain plot
- Young’s modulus
area of thin flexible exoskeleton that allow adjacent podomeres to move relative to one another
articular members rane
fulcrum of arthropod appendage lever
condyle
snapping shrimp speed of claw closure
- 30,000 rpm
- tip moves at 20m/s
- water jets at 30m/s (100km/h)
how a skeletal element accommodates a force depends on
- Shape
2. Material properties
Shapes, skeletal elements
1D - rope
2D - sheet
3D - beams
stress =
force/ unit cross-sectional area
strain
-% extension of material relative to starting length
strength
breaking stress
extensibility
breaking strain
toughness
work to breaking extension
-area under the curve
strain recorded by
application of incremental series of tensional stresses
muscles apply
tension
Myosin is a
mechanoenzyme
-converts chemical energy (ATP) into mechanical work
basic muscle types based on myofilament arrangement
striated
smooth
striated muscle types
- cross striated
- obliquely striated (only inverts.)
- striated organized into sarcomeres
speed of shortening of a striated muscle fibre =
speed of shortening by each individual sarcomere X # of sarcomeres
(short, more, = fast)
muscle with shortest working length
cross-striated fibres
twitch duration
amount of t required for muscle to fully contract, then fully re-extend
twitch duration dependent on
density of SR
muscle with longest working length
smooth fibres
fundamental requirement for sliding of myosin along actin
Ca++
Why is Ca++ fundamental to A/M binding
- tropomyosin blocks myosin binding sites on actin
- Ca++ causes conformational change in tropo. exposing the binding sites
If the density of SR is high within a muscle fibre
- diffusion distance btw SR and myofilaments are short
- twitch duration is short
- twitch frequency is high
catch muscles
- bivalves
- smooth muscle component
- adductor muscle
- anterior byssal retractor muscle
- maintained over long t
- twitchin
dephosphorylation of twitchin causes
it to form a complex with A/M
mixed muscle
- bundles of 2+ types of muscle cells
- ability to change performance characteristics
