Introduction to Marine Life

Finally!!!

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

Some Essential Characteristics of Life

• Made of cells

• Getting energy

• Growth and development

• Reproducing

• Respond to environment

• Maintaining homeostasis

Naturalseasponge.com

Classification of Living Things

• Taxonomy

• 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

5 Kingdom 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.gifhttp://www.biol.tsukuba.ac.jp/~inouye/ino/etc/dinoflagellates.jpg

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

Phytoplankton…single celled plant like orgs (diatoms)

Zooplankton…tiny animal life that drift thru the water and graze on plankton (copepod)

Secondary consumers…filter feed out zoo and phytoplankton (silverside or clam)

Tertiary consumers…predators that feed on smaller fish in level below (bluefish)

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)

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

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

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

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…

Physical Support

• Phytoplankton example• Must life in the upper water column. Must remainbuoyant.• How to resist sinking?...take advantage of water’sviscosity.• Be small…more specifically, have a small volume butlarger surface area…think about an ant with a parachute!• Sinking is a bigger problem in warm water becausewarm 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?

Temperature

• Smaller animals live in warmer seawater

• 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

Salinity

• Stenohaline• Organisms withstand only small variation

in salinity• Typically live in open ocean

• Euryhaline• Organisms withstand large variation in

salinity• Typically live in coastal waters, e.g.,

estuaries

Saltwater vs Freshwater Fish

• 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

RELATIONSHIPS IN THE OCEAN?

CATEGORIES

How and why organisms interact with one another

Interactions between 2 members of the SAME species

Reproduction

Cannibalism

Interactions between 2 members of DIFFERENT species

Parasitism

Mutualism

Predation

Competition

A. SAME species B. DIFFERENT species

C. BOTH CATEGORIES

Competition

InteractionsMale-Female…

Female Choice

Who has the darkest blue

feet?

A

B

C

D

How many fish do you see?

Male

Female

A. NoneB. OneC. Two

How many fish do you see?

MaleFemale

A. NoneB. OneC. Two

Which one is a barnacle?

A B C D

E=all of the aboveF=some of the above

lands externallyburrows in

grows internally: interna stage

impedes growthfeminizes

male

grows internally: interna stage

impedes growth

female

Parasitic Barnacle Life Cycle

externa opens

infect new crab

produces externa stagereproductive replacement.. castration

What is this shrimp doing??

B. committing suicideA. becoming lunch

C. having lunchD. making a mistake

Interactions between organisms can influence the traits and behaviors

of those organisms

RELATIONSHIPS IN THE OCEAN

ReproductionMale-Male interactions influence male sizeMale-Female interactions influence male courtship behavior &

traits used in display male lifestyles

ParasitismHost-parasite interactions influence traits parasites use to “control” hosts behaviors hosts use to avoid parasites…

MutualismInteractions that can help some species

avoid other interactions!

• As an organism gets largerit’s volume increases fasterthan it’s surface area.• The S/V ratio is maximal atsmall sizes• Small S/V ratios help fightagainst sinking but are alsobest for exchanging gasesand nutrients