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Characteristics of All Living Things

• contain matter in a highly organized state

• can capture, store and transmit energy

• are capable of reproduction

• can change through time and adapt to their environment

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Evolution and Life in the Ocean

Earth’s organisms have changed, or evolved, over thecourse of 4 billion years.

Evolution occurs through the process of naturalselection.

The environment favors individuals that are well adapted.Their favorable traits are retained because they contributeto the organism’s reproductive success.

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Living things on Earth share many characteristics. Linnaeusdeveloped some of the systems used to name and classifyorganisms.

• One of the first to use a system of natural classification

• Developed a classification system based on hierarchy

• Developed a system of scientific names for organisms

Classification of Oceanic Life

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The Three Domains

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The six kingdoms ofliving things

Classification of Living Things

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Classification of Oceanic Life

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Major Groups

l Plankton - free floating organisms

l Nekton - swimmers

l Benthos - bottom dwellers (on, in orattached)l Epifauna - live on the bottom (attached or

free)

l Infauna - organisms that live in or burrow inthe sediment

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The marine environment is divided intozones - areas with homogeneous physicalfeatures.

Zones are classified by location and thebehavior of the organisms found there.

Classification of the MarineEnvironment

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Classification of the Marine Environment

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Limiting Factors

Limiting factor - factor found in theenvironment that can be harmful if present inquantities that are too large or too small.

Any factor required for life can become alimiting factor.

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Physical Factors AffectingMarine Life

Any aspect of the physical environment that affects living organisms isa physical factor.

The most important physical factors for marine organisms are:

light dissolved gases

temperature acid-base balance

salinity hydrostatic pressure

dissolved nutrients buoyancy

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Figure 13.8

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Figure 13.9

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Physical Factors AffectingMarine Life

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Body Temperatures

l Ectotherms - cold-blooded organisms;body temperature determined byenvironmental conditions (all marineorganisms except birds and mammals)

l Endotherms - warm-blooded organisms;maintain near-constant body temperature(birds and mammals)

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Biological factors also affect organisms in the ocean.

Some biologic factors that affect ocean organisms:

• feeding relationships

• crowding

• metabolic wastes

• defense of territory

Organisms and OceanTogether

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Organisms in the ocean rely on these processes formany life functions.

Diffusion is mixing due to random molecular movements.

Osmosis is diffusion of water through a membrane

Active transport is the transport of a substance against aconcentration gradient. Active transport requires energy input.

Diffusion, Osmosis, and ActiveTransport

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Diffusion, Osmosis, and Active Transport

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Biogeochemical Cycles

Cycles of elements that are important in lifeprocesses.

Carbon - present in all organic molecules

Nitrogen - found in proteins and nucleic acids

Phosphorus and silicon – found in rigid parts of organisms

Iron and trace metals - used for electron transport

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Carbon Cycle

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Marine Communities

The J-shaped curve represents the growth of a population withoutcompetitors for food or space. The S-shaped curve represents populationgrowth when the population encounters environmental resistance.

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Marine Ecology

* Marine organisms are found in communities, groups of interactingproducers, consumers, and decomposers that share a commonliving space.

* The organisms found in a particular community depend on the physical and biological characteristics of the living space.

* Symbiotic relationships are common in the ocean. Most forms of marine life are actively involved in them.

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Organisms Within Communities

Terms for describing organisms and theirenvironments:

Habitat - an organism’s physical location in itscommunity

Niche - an organism’s role in the community

Biodiversity - the variety of species in a given area

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Physical and Biological Factors

A proper balance of physical and biological factors isimportant for the success of each organism and thecommunity.

Different organisms have different tolerances for specificfactors.

Steno- is a prefix meaning “narrow”. It can be used todescribe organisms that have narrow tolerances forspecific factors

Eury- is a prefix meaning “wide”. It can be used todescribe organisms that have wide tolerances for specificfactors

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Physical and Biological Factors

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Changes in Marine Communities

Marine communities change through time. Changes canoccur slowly due to climate cycles or seafloor spreading,or quickly due to factors such as volcanic eruption.

A climax community is a stable, long establishedcommunity.

If a climax community is disrupted, it may be restoredthrough the process of succession.

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Examples of Marine Communities

l Rocky intertidall Seaweedl Beachl Salt marsh and estuaryl Coral reefl Open oceanl Deep sea floorl Hydrothermal and cold vents

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Rocky Intertidal Communities

The most important physical factor in a rocky intertidal community is therise and fall of tides.

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Seaweed provides protection and highproductivity to the animals that live inseaweed communities.

Seaweed Communities

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Salt marshes and estuaries are rich innutrients, but organisms must cope withfluctuating salinity in theseenvironments.

Salt Marshes and Estuaries

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Many chemosynthetic organisms are found near hydrothermal vents andcold seeps.

Hydrothermal Vent and ColdSeep Communities

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Symbiosis is the close interaction of the lives oftwo species.

Types of symbiotic interactions:

Mutualism - both organisms benefit in theserelationships.An example is sea anemones and anemone fish.

Commensalism - one organism benefits, the other is nothelped or harmed.

Parasitism - one of the organism benefits, but the other isharmed.

Symbiotic Interactions