Ecology and

Ecosystems

Definitions to get started

Essential Questions

1. Explain the two factors that interact in the

study of Ecology.

2. Describe an ecosystem and the 3 specific

parts that make up the areas of an

ecosystem.

3. Describe what limits where organisms can

live.

Ecology

� The science that studies how organisms relate to each other and their environment.

The study of Ecology

� The relationships and interactions of organisms & their environment. � Specifically - abiotic and biotic

� Biotic = living factors

� Abiotic = nonliving factors� temperature, wind, pH, currents,

minerals, salinity, and sunlight.

� Goal: To understand how, through relationships and interactions, changes will affect organisms in the environment.

Ecosystem

� Def: A community of interacting organisms through which energy is transferred.

� distinct entity

� clearly defined physical boundaries

� distinct abiotic conditions

� an energy source

� Examples:

� Estuary and Intertidal

Community

� Def: A collection of different organisms living and interacting in an ecosystem.

� This includes all species and types of organisms.

� Plants, animals, bacteria,

protists, fungi

� Estuaries have:

� Mudflats, Mangrove forest

� Intertidal has:

� Rocky shore, kelp forest

Population

� Def: A group of the same species living and interacting within a community.

� Interaction is key� sometimes two

populations of the same

species live in a single

community.

� Orcas in Puget Sound

Habitat

� Def: The area and conditions in

which you find an organism.

� Some species are adapted to

or occur in very specific

habitats, whereas others range

over a variety of habitats.

� Microhabitat - very small scale

� Tiny crustaceans and worms live

in the spaces between sand grains

� Meiofauna

Niche

� Def: An organism’s role in its habitat

� Very different species can occupy the same niche. � Coral reefs - cleaner-shrimp

and cleaner fish both survive by feeding on the parasites and dead or injured skin of reef fish.

� Habitat = organism’s address

� Niche = job

Energy Flow� Determines how much

energy is available for

organisms at higher trophic

levels.

� Primary producers shape

ecosystem.

� High primary production= � potential for more organisms

at high trophic levels

� And/or more trophic levels.

� Energy flows through an ecosystem, eventually being lost as heat into the water, atmosphere, and space.

Base Nutrient Cycle

� Nutrients aren’t ever lost.

� Crucial elements cycle

through ecosystems

� Carbon cycle is the basis for

most biomass in ecosystems

� Nutrients are limiting

� Energy usually not

� *The most highly productive

marine ecosystems are

found in colder water

***Most limited Nutrient Cycle

� Nitrogen cycle is more limited in marine ecosystems than terrestrial

� Inorganic N2 must be fixed into organic compounds before it can be used

� N2-fixing bacteria live primarily in terrestrial ecosystems.

� To get N2 into ocean –

� Seabird droppings,

erosion, and runoff

Nutrient Cycles are more important

than Energy

� Tropical ecosystems have more energy (sun) available

� oceanic conditions = less nutrients in tropical regions� Upwelling rare

� Temperate coastal waters = less overall sunlight

� receive far more nutrients.

� *The most highly productive marine ecosystems are found in colder water.