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Chapter 13 - Life in the Ocean
characteristics of life
• require energy
– can capture, store, and transmit
– ultimately from sun, earth heat or chemical
reactions
•
•
•
•
highly ordered
reproduce
change through time
adapt to environment
capture and flow of energy
• cell
• energy capture
– from sunlight
– from food
capture and flow of energy
• trophic relationships
– autotrophs
• primary producers
• convert energy to food
– heterotrophs
• consumers & decomposers
• consume food produced by others
capture and flow of energy
• depicting trophic relationships
–
–
–
–
trophic levels
food chain - simple
food web - complex
trophic pyramid
physical (abiotic) factors
• transparency
• dissolved nutrients
• temperature
– exothermic/poiklilothermic/cold-blooded
– endothermic/homeothermic/warm-blooded
• salinity
– extremes - 6 to 30 ppt
physical (abiotic) factors
• dissolved gases
– cold water holds more
– oxygen
•
•
•
•
not easily dissolved
avg - 6 ml/l
plants use at night
large blooms can
result in low oxygen
levels esp. in closed
basins
– CO2
•
•
•
•
easily dissolved
avg - 50 ml/l
60x that of the atmo.
deep water has the
most
– consumers
– downwelling cold
water
– dissolving organisms
physical (abiotic) factors
• pH
• hydrostatic pressure
– avg seawater is about
8
– below CCD
• about 7.6
• lowered by CO2
– animals equalize
inside and outside
pressure
– effects of high
pressure
• gasses more soluble
• enzymes don’t work
• metabolic rates higher
physical (abiotic) factors
– factor interplay
• factors are interlinked
• also influenced by life
biotic factors
• diffusion
– tendancy of a concentration of a substance to
even out
– from high concentration to low
concentration
– faster in warm water
– across membranes
biotic factors
• osmosis
– diffusion of water through a semi-permeable
membrane
– diffusion from high concentration of water
to low concentration of water
biotic factors - osmosis
– isotonic
• concentration inside =
concentration outside
• Some animals in ocean
– hypotonic
• concentration of salts
inside > concentration of
salts outside
• concentration of water
inside < concentration of
water outside
• marine animal in fresh
water
• animal gains water
– hypertonic
• concentration of salts
inside < concentration
of salts outside
• concentration of water
inside > concentration
of water outside
• animal in Great Salt
Lake
• freshwater and some
marine animal in
ocean
• animal loses water
biotic factors - osmosis
– examples and exceptions
• animal with salt concentration less than seawater drinks
seawater
– cells lose water to even concentration in the blood
– animal dehydrates
• fish (?evolved in fresh water?)
– internal salinity 1/3 that of the ocean
– lose water through gills
– solution: drink seawater and excrete salts
• seabirds - excrete salt through glands in skull
• salmon - large kidneys remove excess water during
freshwater phase of life, able to recover salts from food and
urine
biotic factors
• active transport
– movement of dissolved substances from low
concentration to high concentration
– requires energy
biotic factors
• surface-to-volume ratio
– smaller cells are more efficient at transport
and diffusion
– spherical cell
• surface area increases with the square of its
diameter
• volume increases with the cube of its diameter
– cells divide to maintain proper ratio
biotic factors
• gravity and
bouyancy
– density differences
• water = 1 g/cm3
• seawater = 1.025 g/cm3
• marine fish = 1.07
g/cm3
– adaptations
• gas bladders
• strong muscles
• less dense solutions in
body ie.NH3Cl
• food stored in waxes
and oils
biotic factors
• viscosity and movement
– reduce drag to swim
– increase drag to stop sinking
• large surface area to volume ratio
• ornamentation
– warm water less viscous than cold
• water movement
– use of currents to move
classification of environment
• light
– photic
– aphotic
classification of environment
– benthic
• location
– pelagic - open water
• neritic - shallow
• oceanic - deep water
–
–
–
–
epipelagic
mesopelagic
bathypelagic
abyssopelagic
• supralittoral - above
the tidal range
• littoral
• sublittoral
– inner - near shore
– outer - to the edge of
the shelf
• bathyal
• abyssal
• Hadal
Marine Communities
• organization
–
–
–
–
–
organism
population
community
ecosystem
ecosphere
Marine Communities
• organism’s place
– habitat - organisms physical location within
a community
– niche - organisms place (duties) within a
habitat
Marine Communities
• physical and biological factors
– examples
• temp, pressure, salinity
• crowding, predation, grazing, parasitism, shading from
light, waste substances, competition for resources (food,
oxygen, nutrients)
– limiting factors
•
•
•
•
limits chances for success
different for different animals
steno-: tolerant of a narrow range
eury-: tolerant of a wide range
Marine Communities: competition
•
•
•
•
within a species
between species
overlapping niches
results
– survival and reproduction of the most
successful
– less successful moves or dies off
– growth rate and carrying capacity
distribution of organisms
• population density
• species diversity
• distribution patterns
– random
• rare
• same conditions must exist throughout the community
– clustered
• most common
• individuals of a spies cluster near optimal conditions
– uniform - vary rare
• motile vs sessile
species interaction
• trophic
• symbiotic
– often species specific
– types
• mutualism
• commensalism - symbiont benefits, host is not harmed
• parasitism - host is harmed
• dependencies
• one species depends on another (for food) but
they do not live in extended contact
change in marine communities
• usually slow
– marine conditions rarely change rapidly
– some rapid processes - volcanoes, earthquakes,
landslides
• climax community
– stable
– long established
– reestablished through succession
• may be slightly different
evolution
• development of complex life forms
– through mutation and selection
• natural selection - survival of the
– fittest (for a niche)
– luckiest
– combination
• species
– reproductively isolated group of living organisms
• speciation & extinction
• divergent & convergent evolution
• phyletic gradualism & punctuated equilibrium
Organic evolution: observations
• sedimentary rocks
– deposited in layers
– oldest layers are on the bottom
– layers may be correlated with other sedimentary
layers
• fossil record
– oldest rocks have only simple fossils
– younger rocks have more organisms similar to those
living today (at levels from species to kingdom)
– fossils record includes appearances and extinctions
of many species
Organic evolution: observations
• geographic distribution of organisms
– many organisms are similar but unique
– they are confined to specific areas (islands, continents,
water bodies)
– includes modern and fossil organisms
– distribution has changed through time
Organic evolution: observations
• anatomy
– cell structure is similar in all living
organisms
– embryology - embryos of mammals, birds,
and reptiles are very similar
– homologus organs - similar organs, different
functions
– vestigal organs - no purpose in one, purpose
in another
Organic evolution: observations
• genetics
– structure of DNA and RNA is the same in all
living organisms
– similarity in genetic code varies between
organisms (some organisms are more similar
than others)
Organic evolution: conclusions
• the characteristics of populations of
living organisms have changed through
time
– life has become more complex
– life has become more diverse
– this is excepted as a factual observation
• all life is related
Natural selection: observations
• populations of organisms display a variety of
characteristics
– characteristics may be useful, not useful, or
detrimental
– the variety is reflected in an organisms genes
• mutations
– produced by random alteration of genes and passed
to offspring during reproduction
– provides variety
Natural selection: observations
• artificial selection
– domesticated plants and animals can be bred
to favor certain characteristics
– populations of wild and domestic plants and
animals develop characteristics that favor
their survival
Natural selection: observations
• the natural environment
– organisms with favorable characteristics for
their niche are more likely to thrive and
reproduce
– organisms with unfavorable characteristics
are less likely to thrive and reproduce
– a new niche or stress on an existing niche
will enhance selection
Natural selection: conclusion
• the natural environment provides
conditions that result in evolution
through the process of natural selection
Evolutionary trends
• speciation & extinction
• divergent & convergent evolution
• phyletic gradualism & punctuated
equilibrium
Natural selection: speciation
• a population has a gene pool
• members of the population interbreed
• the population may become isolated from
others of a species
– development of niches & resource partitioning
– migration
– development of physical barriers
• populations may be selected
– by stress
– by opportunity
• isolation may result in genetic divergence
Natural selection: extinction
• stress on limiting factors reduce or
destroy a population
• evolution into subsequent species
(pseudo-extinction)
Phylogeny
• relationships between organisms can be
determined using
– genetics
– anatomy & physiology
– Fossils
Evolutionary trends
• speciation & extinction
• divergent & convergent evolution
• phyletic gradualism & punctuated
equilibrium
primary productivity
• photo- and chemo-synthesis
primary productivity
• measurement
– grams of carbon bound
(appx 10% of producers
mass)
– per square meter of ocean
surface
– per year
• sampling
– measure oxygen produced
in a suspended set of
bottles
– follow carbon through the
process (in the lab)
• breakdown
– phytoplankton - 9098%
– seaweeds - 2-10%
– chemosynthesis - 1%
• production
– avg - 75 to 150
g(C)/m2/yr
primary productivity - limiting factors
• water - plenty
• CO2 - plenty
• nutrients
–
–
–
–
non-conservative - change with bio activity
nitrates, phosphates, silicates
lost to organisms then to the depths
replaced by runoff, upwelling, atmosphere
primary productivity - limiting
factors
• light
– quantity - can have too much or too little
– quality - color
• red and violet are best absorbed by green
– quantity and quality vary with
• depth
– red is absorbed near the surface
• concentration of organisms
• concentration of sediment
– adaptations: accessory pigments - absorb light for
chlorophyll
Plankton
• floaters and weak swimmers
• producers and consumers
• collection and study
– plankton nets
– microscopic
phytoplankton
• autotrophs
• depth of greatest productivity
– 20 m at noon
– 5-10 m daily
• compensation depth
– energy consumed = energy produced
– go below - die
global distribution of
productivity
• near cont. shelves
– upwelling & runoff
– 1 g(C)/m2/day
• tropics
–
–
–
–
much sunlight & CO2
low nutrients
30 g(C)/m2/yr
reefs - tightly cycle
nutrient through the reef more productive
• polar
– low sun angle
– dark winter, long days in
summer
– upwelling
– seasonal blooms
• temperate and subpolar
– good mix of light and
nutrients
– seasonal
phytoplankton - dinoflagellates
• swim with whirling flagella
• reproduce through fission
• nutrients can causes blooms
– red tides
• some are bioluminescent
phytoplankton - diatoms
• SiO2 shell (frustule)
– two perforated valves
•
•
•
•
highly energy efficient
store energy as oils - for floating
some are benthic
reproduction
–
–
–
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fission - generate new shell inside the parent
smaller with each generation
size gets too small
sexually reproduce new offspring with no shell
phytoplankton - nanoplankton
• very small
– coccolithopores - carbonate shells made of
plates - chalk
– silicoflagellates
Plants
• vascular
– sap
– transport substances through vessels
• non-vascular
– algae
– “seaweed”
Plant structure
• problems
– shock
– abrasion
– water drag
• covered with a mucus-like substance
– lubricates
– retards drying
– deters grazers
Plant structure
• fluids
– algae - isotonic
– angiosperms hypotonic
• thermal stress - heat
– speeds metabolic rate
– may not have enough
oxygen available at
night
– damages pigments
• anchorage/substrate
– algae - solid base
– rooted plants unconsolidated base
• depth
– less than 2% of ocean
floor is shallow
enough
Plants - seaweeds
• thallus (plant)
–
–
–
–
blade
stipe
gas bladder
holdfast
• reproduction
– alternate sexual and
asexual
• zonation: due to depth &
other factors
• classification
– chlorophytes - green
– phaeophytes
• tan or brown
• kelp
• some are free-foating
– rhodophytes
• red
• most of world’s
seaweeds
Plants - angiosperms
•
•
•
•
flowering plants
moved from land to water
live at the surface
structure
– leaves
– stem
– roots: extract nutrients from the substrate
• types
– sea grasses
– mangroves
animals - classification
• artificial systems
– exterior similarities
– functions, colors, etc.
• natural systems
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–
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originally based on structural and biochemical similarities
now based on DNA
Linnaeus
K, P, sub-P, C, O, F, G, S
scientific name
• genus-species
• permanent
• unchanging words - usually Latin
• internationally monitored
animals - key events
• oxygen in the ocean and atmosphere
– 2 BYA - 1% oxygen
– 400 MYA - 20% oxygen
– thanks to photsynthetic oxygen
• metazoans - multi-cellular
– soft-bodies - first appx. 600 MYA
• Ediacara Hills, Aust.
• bizzare
– segmented worms
– shelled animals - first appx. 550 MYA
– arthropods - trilobites
zooplankton
• consumers
• most animal groups represented
• create oxygen minimum zone just below the
well-lighted surface zone
• size
– most less than 1 cm
– some > 1 cm - macroplankton
• life cycle
– holoplankton - spend entire lives as plankton
– meroplankton - spend part of life as plankton
K. Protista
(zooplankton)
• foraminifera
– amoeba-like
– carbonate shells
• radiolarians
– amoeba-like
– spike-like pseudopods
• amoebas
P. Porifera
• sponges
• suspension feeders
• structure
–
–
–
–
collar cells - capture and digest
amoeboid cells - transport food
surface cells - protect
spicules and spongin - support
P. Cnidaria
• jellyfish, anemones, corals
• radial symmetry
• structure
–
–
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stinging cells - capture food, repel predators
some nerve cells
mouth/anus
digestive cavity
• form - polyp or medusa
P. Platyhelminthes
•
•
•
•
flat worms - tape worms
parasitic & free-living
bilateral symmetry
structure
– mouth/anus
– nervous system, brian, eyespots
– no resp or excret systems
P. Nematoda
• roundworms
• structure
– flow-through digestive system
• important sediment-feeders
P. Annelida
• segmented worms
• structure
– head
– flow-through digest
– segment with circ, excret, nerv, musc, repro
systems
P. Mollusca
• characteristics
–
–
–
–
–
soft body
most have a shell
bilateral symmetry
flow-through digest
circ, excret, nerv, musc, repro systems
• classes
–
–
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polyplacophora
gastropoda
bivalvia
cephalopoda
P. Arthropoda
• characteristics
– exoskeleton
• must molt to grow
– striated muscle
– articulated
• classes
– insecta - poorly represented at sea
– Crustacea
• crabs, krill, lobsters, barnacles
• copepods
– zooplankton
– crustaceans
– 70% of animals
P. Echinodermata
• five-way symmetry
• start as bilaterally symmetrical
• classes
– asteroidea - sea stars
• tube feet
• water vascular system - locomotion & feeding
– ophiuroidea - brittle stars
• widely distributed
– echinoidea - sea urchins and sand dollars
– holothuriodea - sea cucumbers
other Phyla
• Bryozoa - important ancient reef builders
• Brachiopoda - very important bivalved
shell animals in the Paleozoic
• Hemichordata - important transitional
phyla
P. Chordata
• invert
– tunicates - suspension feeders
– lancelets
• example: amphioxis
• transitional species
Fish (vertebrates)
• agantha
– jawless fishes
– lampreys, hagfish
• condrichthyes
– cartiliginous fishes
– sharks, skates, rays, chimera
Fish (vertebrates)
• osteichthyes - bony fishes
–
–
–
–
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shape - antidrag
movement - eel-like or hinged-tail
maintenance of level - swimming or gas bladder
gas exchange - gill membranes
osmotic problems (advanced fish) - hypotonic (lose
water) - drink water & excrete salt - conservative
kidneys
– feeding & defense - sight, hearing (inc. lateral line),
coloration (cryptic coloring and top/bottom countershading), schooling
amphibians
• none exclusively marine
• adapted to land and freshwater
• permeable skin
reptiles
• characterisics
– lungs
– scales
– salt glands
• groups
– sea turtles
• 8 species
• all endangered
• streamlined shells, flippered feet
– marine crocodiles - one species, in tropical W Pacific
– marine lizards - only Galapagos marine iguana
– sea snakes
• 50 known species
• highly venomous
birds
• sea birds - 270 species
• warm-blooded
• characteristics
– salt-excreting glands
– avoid land except for breeding
– obtain almost all food from the sea
• groups
–
–
–
–
Tubenoses - albatrosses & petrels
pelicans et. al.
gulls & puffins
penguins
mammals
• characteristics of marine mammals
– streamlined
– warm-blooded
– resp. system modified to collect and retain
large quantities of oxygen
Mammal orders
• cetacea
– evolved from early ungulates (horses and sheep)
– horizontal tail flukes that move up and down
– toothed whales - orca, dolphins, porpoises - echo
location
– baleen whales - filter-feeders
• carnivora
– pinnipedia - seals, sea lions, walruses
– fissipedia - sea otters, polar bears
• sirenia - mantees
rocky intertidal
• problems
–
–
–
–
wave shock
wetting and drying
land and water predators
daily and annual sediment movement
• benefits
– lots of food
– stirred up food and gasses
– many niches
• very diverse
• zoned
sand and cobble beaches
• problems
– as above
– loose bottom
– moving sand
• abrasive
• mixed with food
• much less habitable
salt marshes and estuaries
• salinity can vary greatly
– salty - brackish - fresh
– vertically and horizontally
– leads to complex zonation
• isolation at low tide
– raises salinity
– raises temp
• estuaries
– highly diverse and productive
– marine nurseries
open ocean
• top 200 meters
– 83% of biomass
– almost all productivity
• deep scattering layer
–
–
–
–
top of the dark zone
move up to feed at night
can see shadows of prey above
may have light organs to mask own shadow
• bathypelagic
– little food available
– bizarre animals
– little known
deep sea floor
•
•
•
•
•
dark
cold
slightly hyper saline
weak currents
organisms
– blind
– many scavangers, some predators
– low metabolic rate
• may eat less than once per year
• may live to be 100
– large
– fragile
vent communities
•
•
•
•
discovered in 1977
chemosynthetic producers
superhot water (350EC)
some animals (tube worms, clams) house
chemosynthetic bacteria for food
reefs
•
•
•
•
materials are tightly cycled
corals
other animals
types
– fringing
– barrier
– atolls