Download Introduction to Marine Life

Introduction to Marine Life
Some Essential Characteristics of Life
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Made of cells
Getting energy
Growth and development
Reproducing
Respond to environment
Maintaining homeostasis
Ocean Ecosystem
• An ecosystem is a level of organization that
includes living things and their environment
• Living things cannot exist without their
environment
• Most of our planet is covered by the ocean or
marine ecosystem
Structure and Function of an
Ecosystem
What the ecosystem is made up of and how it works are linked and influence
each other…
STRUCTURE
FUNCTION
Abiotic factors
Interactions between living
things
Biotic factors
Cycling
ABIOTIC and BIOTIC FX
Physical or non-living parts of the
environment that influence living things are
called abiotic factors
examples:
Living factors which influence living things are
called biotic factors
examples:
Abiotic Factors in the Ocean
• Inorganic nutrients like: C,N,H,P,S,Fe,Si
• Motion in the ocean: upwelling, currents,
tides
• Dissolved materials like gases and salts
• Climate: temperature, light, pressure
• Variations in time and space
Biotic Factors
• Characteristics of living things
• Diversity: Many different types of species
• Interactions between living things:
symbiosis, competition and predation
LAND vs OCEAN
• Ocean is wetter than land
– Materials can be dissolved in ocean water
– gametes can be dispersed more easily
– Harder for smaller things to move through water
• Ocean is more vast than land
– Harder to find mates and food
• Ocean is more supportive than land
– Body structure will be different than land animals
• Living in aquatic environment will shape biology
and adaptations of marine life
Salinity:
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Stenohaline (steno-)
Organisms withstand only small variation in
salinity
Typically live in open ocean
Euryhaline ( eury- )
Organisms withstand large variation in
salinity
Typically live in coastal waters, e.g.,
estuaries
Salinity:
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Osmoconformers
Do not expend energy removing water or salt from
their bodies
Gain or lose water at a regular rate/ internal
salinity similar to seawater
Typically stenohaline
Osmoregulators
Maintain a stable internal osmolarity by
homeostasis
Marine examples maintain an internal salinity
lower than seawater
Typically euryhaline
Saltwater vs Freshwater Fish
Marine Fish continued…
• Need to maintain body water
• Marine fish are at risk of ‘dehydrating’, and
freshwater fish are at risk of having their
cells burst from the uptake of too much
water
Temperature
Ectotherm ( ecto-)
• Body temp varies with the temp of their
environment
• Can thrive even at higher latitudes by
overwintering, migration, burrowing,
natural antifreeze
• Examples: most fish, amphibians, reptiles
and most invertebrates
Temperature
Endotherm ( endo-)
• Body temp is produced metabolically ie:
breakdown from food
• In some cases animal needs 5 times the food
energy to stay alive as compared to an
ectotherm of same weight
• Examples: All birds and mammals; tuna;
skunk cabbage; some insects like butterflies
and bees
Temperature
• Species in warmer seawater tend to be
smaller then relatives in colder water
• More appendages in warmer seawater
• Tropical organisms grow faster, live shorter,
reproduce more often
• More diversity in warmer seawater
• Total amount of life is greater in cooler
seawater (lots of nutrients)
Temperature
• Stenothermal
– Organisms withstand small variation in temp
– Typically live in open ocean
• Eurythermal
– Organisms withstand large variation in temp
– Typically live in coastal waters
REPRODUCTION
• Animals in marine environment have many
strategies for “success”
• Egg production is “costly” and there are
tradeoffs for each strategy for reproduction
• R-strategy….produce many offspring with
low probability of survival
• K strategy… produce less young but heavily
invested in offspring so higher chance of
survival
More on Reproduction
Specific methods of producing offspring…
• Fission, budding, eggs hatching externally,
eggs hatching internally, live births, some
marine animals are born in freshwater,
some are born on land, etc…
• Reproducing in water allows for a lot of
external reproduction
GROWTH and DEVELOPMENT
• Life history…cycle from birth to
reproduction
• Animals often look very different in early
life history from their adult form
• Many marine orgs undergo metamorphosis
dependent on environmental conditions
• Larval stages are often food for higher
trophic levels
Size in the Ocean
• As an organism gets larger
it’s volume increases faster
than it’s surface area.
• The S/V ratio is maximal at
small sizes
• Small S/V ratios help fight
against sinking but are also
best for exchanging gases
and nutrients
Physical Support
• Phytoplankton example
• Must live in the upper water column. Must remain
buoyant.
• How to resist sinking?...take advantage of water’s
viscosity.
• Be small…more specifically, have a small volume but
larger surface area…think about an ant with a parachute!
• Sinking is a bigger problem in warm water because
warm water is less viscous.
Staying Afloat
• Appendages to increase surface area
• Oil in micro-organisms to increase buoyancy
• Fewer support
structures in
cold rather than
warm seawater
Physical Support
• Larger orgs (swimmers)
are streamlined
• Flattened / tapered bodies
• Would you rather
be a Ferrari, or a
minivan?
Naturalseasponge.com
Classification of Living Things
• Taxonomy / Systemactics
• Every organism has a two part name unique
to itself
• Genus species or Genus species
– Prevents confusion if a species is known by
many common names
• There are several ways to classify animals at
higher levels of organization
Evolution of Life
• Evidence supports that first life evolved in
the oceans ~3.5 bya
– Photosynthesis began 2.5 mya
– For 2.3 by all life was single celled
– About 1.2 bya more complex mutlicellular life
evolved
– Life forms have become more diverse
– Fossil record reveals patterns of evolution and
extinction
Oceans throughout Geologic Time
• http://ocean.si.edu/sites/default/files/styl
es/663x/public/photos/603_P01_G02w.jpg
?itok=1ZEpu8Ij
Kingdoms of Life Classification
Cellular Differences
• Prokaryotes – Kingdom Moneran / bacteria
group
– Lack a nucleus and membrane bound organelles
• Eukaryotes- All other kingdoms
– Have a nucleus and membrane bound organelles
http://io.uwinnipeg.ca/~simmons/1116/images/bactloco.gif
http://www.biol.tsukuba.ac.jp/~inouye/ino/etc/dinoflagellates.jpg
Lifestyles of Marine Orgs
• Planktonic
• Nekton
• Benthic
Plankton
• Most biomass on Earth consists of plankton
• Phytoplankton
– Autotrophic (diatoms, coccolithophores)
• Zooplankton
– Heterotrophic
• Bacterioplankton
– The most abundant photosynthetic organism on earth
• Half of all the photosynthetic biomass in ocean
• Virioplankton
– Viruses (mostly attack plankton)
Types of Plankton
• Holoplankton
– Entire lives as plankton
– Ex. copepod
• Meroplankton
– Part of lives as plankton
– Juvenile or larval stages
– Ex. Blue crab
interactive.usc.edu/.../archives/2005/08/
Nekton
• Independent swimmers
Ex…fish, marine mammals
Benthos
• Live on surface of sea floor or buried in
sediments
• Most abundant in shallower water
• Ex. Marine worms, crabs, lobsters
FOOD WEBS
• Trophic level… position or feeding level
• Producers…base of the food web and create
sugars from sun’s energy or chemical
energy
• Consumers…eat other living things
• Food webs are the connection between
many food chains in an ecosystem
Marine Food Chain
Apex predators…efficient hunters, opportunistic feeding habits (eat what is available)
(tuna, sharks, billfish)
Higher level consumers…predators that feed on smaller fish in level below
(bluefish or flounder)
Tertiary consumers…predators that feed on smaller fish in level below (bluefish)
Secondary consumers…filter feed out zoo and phytoplankton (silverside or
clam)
Zooplankton…tiny animal life that drift thru the water and graze on plankton (copepod)
Phytoplankton…single celled plant like orgs (diatoms)
10% Rule
• Higher trophic level orgs…larger in size and
fewer in number than those at lower levels.
• each trophic level transfers 10% of its energy
• each level supports a smaller total biomass to
compensate loss of food value.
• 90% loss is used for growth, reproduction,
repair etc…
What Does 10% Rule Mean?
• 100,000 lbs of phytoplankton feed 10,000 lbs of
copepods,
• 10,000 lbs copepods feed 1,000 lbs of silversides
• 1,000 lbs silversides feed 100 lbs of mackerel
• 100 lbs of mackerel feed 10 lbs of bluefin tuna
• tuna nourishes only one pound of apex predator
OTHER FOOD ROLES
• Decomposers… break down food and
nutrients left over from predation or in dead
orgs or waste
• Omnivores…feed on consumers and
producers
• Microbial loop…bacteria help make
available even smaller nutrients called DOM
(dissolved organic matter) that would
otherwise be lost
Gas Exchange and Carbon Cycle
• Oceans absorb and store large amounts of
CO2
– Contain about 50 X the amount found in the
atmosphere
• biological pump -some of the absorbed CO2
is used in the food web by phytoplankton, or
used to make shells and then consumed and
pooped out
• gas is trapped in the deep ocean
(sequestered) until brought to surface by
currents
Ocean Acidification
• CO2 is changed to carbonic acid as it
dissolves in seawater
– More CO2 dissolving, more acidic ocean is
becoming
– 30% increase in acidity since IR
• Marine life that produce calcium carbonate
shells are negatively impacted by
increasing acidity (coral, clams, mussels,
oysters, some algae)
• The photos below show what happens to a
pteropod’s shell when placed in sea water
with pH and carbonate levels projected for
the year 2100. The shell slowly dissolves
after 45 days. Photo credit: Used with
permission, National Geographic Images