Chapter 13 - Life in the Ocean

Chapter 13 - Life in the OceanChapter 13 - Life in the Ocean

characteristics of lifecharacteristics 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 energycapture and flow of energy

• cell

• energy capture– from sunlight– from food


• trophic relationships– autotrophs

• primary producers

• convert energy to food

– heterotrophs• consumers & decomposers

• consume food produced by others


• depicting trophic relationships– trophic levels– food chain - simple– food web - complex– trophic pyramid

physical (abiotic) factorsphysical (abiotic) factors

• transparency

• dissolved nutrients

• temperature– exothermic/poiklilothermic/cold-blooded– endothermic/homeothermic/warm-blooded

• salinity– extremes - 6 to 30 ppt


• 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


• pH– avg seawater is about

8

– below CCD• about 7.6

• lowered by CO2

• hydrostatic pressure– animals equalize

inside and outside pressure

– effects of high pressure

• gasses more soluble

• enzymes don’t work

• metabolic rates higher


– factor interplay• factors are interlinked

• also influenced by life

biotic factorsbiotic factors

• diffusion– tendancy of a concentration of a substance to

even out– from high concentration to low

concentration– faster in warm water– across membranes


• osmosis– diffusion of water through a semi-permeable

membrane– diffusion from high concentration of water

to low concentration of water

biotic factors - osmosisbiotic 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 - osmosisbiotic 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


• active transport– movement of dissolved substances from low

concentration to high concentration– requires energy


• 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


• 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


• 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 environmentclassification of environment

• light– photic– aphotic

classification of environmentclassification of environment

• location– pelagic - open water

• neritic - shallow

• oceanic - deep water– epipelagic

– mesopelagic

– bathypelagic

– abyssopelagic

– benthic• supralittoral - above

the tidal range

• littoral

• sublittoral– inner - near shore

– outer - to the edge of the shelf

• bathyal

• abyssal

• Hadal

Marine CommunitiesMarine Communities

• organization– organism– population– community– ecosystem– ecosphere


• organism’s place– habitat - organisms physical location within

a community– niche - organisms place (duties) within a

habitat


• 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: Marine Communities: competitioncompetition

• 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 organismsdistribution 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 interactionspecies 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 communitieschange 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

evolutionevolution

• 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: observationsOrganic 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


• 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


• 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


• 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: conclusionsOrganic 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: observationsNatural 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


• 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


• 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: conclusionNatural selection: conclusion

• the natural environment provides conditions that result in evolution through the process of natural selection

Evolutionary trendsEvolutionary trends

• speciation & extinction

• divergent & convergent evolution

• phyletic gradualism & punctuated equilibrium

Natural selection: speciationNatural 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: extinctionNatural selection: extinction

• stress on limiting factors reduce or destroy a population

• evolution into subsequent species (pseudo-extinction)

PhylogenyPhylogeny

• relationships between organisms can be determined using– genetics– anatomy & physiology– Fossils

Evolutionary trendsEvolutionary trends

• speciation & extinction

• divergent & convergent evolution

• phyletic gradualism & punctuated equilibrium

primary productivityprimary productivity

• photo- and chemo-synthesis

primary productivityprimary 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 - 90-

98%

– seaweeds - 2-10%

– chemosynthesis - 1%

• production– avg - 75 to 150

g(C)/m2/yr

primary productivity - primary productivity - limiting factorslimiting 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 - primary productivity - limiting limiting factorsfactors• 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

PlanktonPlankton

• floaters and weak swimmers

• producers and consumers

• collection and study– plankton nets– microscopic

phytoplanktonphytoplankton

• 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 global distribution of productivityproductivity• 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 - dinoflagellatesphytoplankton - dinoflagellates

• swim with whirling flagella

• reproduce through fission

• nutrients can causes blooms– red tides

• some are bioluminescent

phytoplankton - diatomsphytoplankton - diatoms

• SiO2 shell (frustule)– two perforated valves

• highly energy efficient• store energy as oils - for floating• some are benthic• reproduction

– fission - generate new shell inside the parent– smaller with each generation– size gets too small– sexually reproduce new offspring with no shell

phytoplankton - nanoplanktonphytoplankton - nanoplankton

• very small– coccolithopores - carbonate shells made of

plates - chalk– silicoflagellates

PlantsPlants

• vascular– sap– transport substances through vessels

• non-vascular– algae– “seaweed”

Plant structurePlant structure

• problems– shock– abrasion– water drag

• covered with a mucus-like substance– lubricates– retards drying– deters grazers

Plant structurePlant 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 - seaweedsPlants - 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 - angiospermsPlants - 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 - classificationanimals - classification• artificial systems

– exterior similarities

– functions, colors, etc.

• natural systems– 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 - animals - key eventskey 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

zooplanktonzooplankton• 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.K. ProtistaProtista

(zooplankton)• foraminifera

– amoeba-like– carbonate shells

• radiolarians– amoeba-like– spike-like pseudopods

• amoebas

P. PoriferaP. Porifera

• sponges

• suspension feeders

• structure– collar cells - capture and digest– amoeboid cells - transport food– surface cells - protect– spicules and spongin - support

P. CnidariaP. Cnidaria

• jellyfish, anemones, corals• radial symmetry• structure

– stinging cells - capture food, repel predators– some nerve cells– mouth/anus– digestive cavity

• form - polyp or medusa

P. PlatyhelminthesP. Platyhelminthes

• flat worms - tape worms

• parasitic & free-living

• bilateral symmetry

• structure– mouth/anus– nervous system, brian, eyespots– no resp or excret systems

P. NematodaP. Nematoda

• roundworms

• structure– flow-through digestive system

• important sediment-feeders

P. AnnelidaP. Annelida

• segmented worms

• structure– head– flow-through digest– segment with circ, excret, nerv, musc, repro

systems

P. MolluscaP. Mollusca• characteristics

– soft body– most have a shell– bilateral symmetry– flow-through digest– circ, excret, nerv, musc, repro systems

• classes– polyplacophora– gastropoda– bivalvia– cephalopoda

P. ArthropodaP. 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. EchinodermataP. 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 Phylaother Phyla

• Bryozoa - important ancient reef builders

• Brachiopoda - very important bivalved shell animals in the Paleozoic

• Hemichordata - important transitional phyla

P. ChordataP. Chordata

• invert– tunicates - suspension feeders– lancelets

• example: amphioxis

• transitional species

Fish (vertebrates)Fish (vertebrates)

• agantha– jawless fishes– lampreys, hagfish

• condrichthyes– cartiliginous fishes– sharks, skates, rays, chimera

Fish (vertebrates)Fish (vertebrates)

• osteichthyes - bony fishes– 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 counter-shading), schooling

amphibiansamphibians

• none exclusively marine

• adapted to land and freshwater

• permeable skin

reptilesreptiles

• 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

birdsbirds

• 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

mammalsmammals

• characteristics of marine mammals– streamlined– warm-blooded– resp. system modified to collect and retain

large quantities of oxygen

Mammal ordersMammal 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 intertidalrocky 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 beachessand and cobble beaches

• problems– as above– loose bottom– moving sand

• abrasive

• mixed with food

• much less habitable

salt marshes and estuariessalt 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 oceanopen 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 floordeep 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 communitiesvent communities

• discovered in 1977

• chemosynthetic producers

• superhot water (350C)

• some animals (tube worms, clams) house chemosynthetic bacteria for food

reefsreefs

• materials are tightly cycled

• corals

• other animals

• types– fringing– barrier– atolls

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Chapter 13 - Life in the Ocean