Characteristics of All Living Things
Contain matter in a highly organized state
Capture, store and transmit energy; all organisms require energy
Capable of reproduction
Change through time and adapt to their environment
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Evolution and Life in the Ocean
Life originated in the ocean.
Organisms have evolved over the last 4 billion years through the process of natural selection.
The environment favors individuals that are well adapted. Microorganisms are the most successful life forms.
Sometimes, catastrophic events wipe out many organisms, regardless of adaptation.
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Classification of Oceanic Life
Linnaeus developed the system used to name and classify organisms
System is based on a hierarchy: kingdom, phylum, class, order, family, genus and species
Uses scientific names for organisms; a species consists of the genus name combined with a trivial name.
Formal names are in Latin; common names are in local languages
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Classification of Living Things
The six (or five) kingdoms of organisms
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The Three Domains of Life
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Classification of Oceanic Life
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Classification of the Marine Environment
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Benthic (bottom) and Pelagic (water column) Environments
Benthic environment - divided by depth into: intertidal zone, sublittoral zone, bathyal zone, abyssal zone, and the hadal zone.
Pelagic environment - divided broadly into: neritic zone and oceanic zone, and more specifically into the epipelagic, mesopelagic, bathypelagic, abyssalpelagic, and hadalpelagic zones.
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Zones Based on Depth of Light Penetration
Photic zone - depth where light is sufficient for photosynthesis. Dysphotic zone - illumination is too weak for photosynthesis. Aphotic zone - no light from the surface because it is all absorbed by the water above.
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Major Lifestyles
Plankton - free floating organisms; phytoplankton and zooplankton Nekton - swimmers Benthos - bottom dwellers (on, in or attached) Epifauna - live on the bottom (attached or free) Infauna - organisms that live in or burrow in the sediment
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Physical and Biological Factors
A proper balance of physical and biological factors is important for the success of each organism and the community.
Different organisms have different tolerances for specific factors.
Steno- is a prefix meaning “narrow”. It describes organisms that have narrow tolerances for specific factors
Eury- is a prefix meaning “wide”. It describes organisms that have wide tolerances for specific factors
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Limiting Factors
Limiting factor - physical or chemical factor in the environment that can limit or harm organisms if present at levels that are too large, too small or too extreme.
Any factor required for life can become a limiting factor.
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Physical Factors Affecting Marine Life
Any aspect of the physical environment that affects organisms is a physical factor.
The most important physical factors for marine organisms are: light dissolved gases temperature acid-base balance salinity hydrostatic pressure nutrients buoyancy
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Figure 13.9
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Temperature
Temperature - controls distribution, degree of activity and reproduction of an organism
Ectotherms - cold-blooded organisms; body temperature determined by environmental conditions (all marine organisms except birds and mammals)
Endotherms - warm-blooded organisms; maintain near-constant body temperature (birds and mammals)
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Temperature
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Biogeochemical Cycles
Cycles of elements that are important in life processes.
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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Figure 13.8
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Physical Factors Affecting Marine Life
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Biological Factors
Biological factors also affect organisms in the ocean.
Some biologic factors that affect marine organisms:
• feeding relationships
• crowding
• metabolic wastes
• defense of territory
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Diffusion, Osmosis, and Active Transport
Organisms in the ocean rely on these processes for many 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 a concentration gradient. Active transport requires energy input.
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Diffusion, Osmosis, and Active Transport
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Marine Ecology
Ecology: Inter-relationships between the physical and biological aspects of the environment
Marine organisms live in communities - groups of interacting producers, consumers, and decomposers sharing a common living space
Ecosystem - total environment including the biota (all living organisms) and the non-living physical and chemical aspects
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 their environments:
Habitat - an organism’s physical location in its community
Niche - an organism’s role in the community
Biodiversity - the variety of species in a given area
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Symbiotic Interactions Symbiosis is the close interaction of the lives of two species.
Types of symbiotic interactions:
Mutualism - both organisms benefit in these relationships.
Commensalism - one organism benefits, the other is not helped or harmed.
Parasitism - one organism benefits, but the other is harmed.
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Marine Communities
The J-shaped curve represents the growth of a population without competitors for food or space. The S-shaped curve represents population growth when the population encounters environmental resistance. 28
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Changes in Marine Communities
Marine communities change through time. Changes can occur slowly due to climate cycles or seafloor spreading, or quickly due to factors such as volcanic eruption.
A climax community is a stable, long established community.
If a climax community is disrupted, it may be restored through the process of succession.
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Competition
Competition can occur among members of the same species, or 30 between members of different species.
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Examples of Marine Communities
Rocky intertidal Seaweed Beach Salt marsh and estuary Coral reef Open ocean Deep sea floor Hydrothermal and cold vents
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Intertidal Communities
Generally arranged in distinctive bands or vertical zonation
Zonation reflects amount of time the area is submerged and ability of organisms to survive exposure.
Benthic communities also vary based on substrate (bottom material). Some organisms are adapted to rocky, sandy, or muddy sea bottoms.
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HIGH TIDE
LOW TIDE
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Rocky Intertidal Communities
The most important physical factor in a rocky intertidal community is the34 rise and fall of tides.
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Seaweed Community
Seaweed provides protection and high productivity to the animals that live in the communities
A complex interaction among kelp, sea urchins, and sea otters controls the kelp community
Sea urchins feeding on kelp detach them from their holdfast and devastate the kelp beds
Sea otters feed on sea urchins and control the size of their population
Where sea otters abound, sea urchins are few, kelp beds thrive and sea otters feed mainly on fish.
Where sea otters are few, sea urchins abound and kelp bed are thin. Sea otters then mainly eat sea urchins. 35
Sand and Cobble Beach Communities
Beaches are a demanding physical environment for organisms.
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Salt Marshes and Estuaries
Salt marshes and estuaries are rich in nutrients, but organisms must cope with fluctuating salinity in these environments.
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Coral Reefs
More than one million species inhabit coral reef ecosystems.
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Open Ocean
Consumers in the open ocean depend on the productivity of organisms in the water column above.
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The Deep-Sea Floor
The deep-sea floor is dark, cold, and highly pressurized, yet many species including the blind tripod fish are found in this harsh environment. 40
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Hydrothermal Vent and Cold Seep Communities
Many chemosynthetic organisms are found near hydrothermal vents and cold seeps. 41
Organisms rely on both the physical and biological factors in their environment for survival.
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