Unit 2

Energy Flow & Nutrient Cycling.

All ENERGY begins with the SUN

The sun is the primary source of energy for most living things.

Organisms get their energy from the sun or eating other things.

Law of Conservation of Energy/Matter

Energy cannot be created nor destroyed it simply transfers from one form to another.

Lg. Fish Sm. Fish plankton sun

5 Levels of Environmental Organization of Life

Organisms

Populations

Communities

Ecosystems

Biosphere

Biotic Factors

• Biosphere – life-supporting layer of Earth• Biotic factors – ALL living organisms in a biosphere.

Abiotic Factors

• Nonliving factors in an environment• Examples:– Air currents– Temperature– Moisture– Light– Soil

Energy Connection• Producer - an organism that makes its own

food; plants are producers.• Consumer - an organism that needs to eat

other organisms (plant or animal) for its food.• Decomposer - organisms that break down

previously living organisms and their waste; bacteria and fungi are decomposers.

Energy PyramidTransfer of Energy

Only 10% of energy is transferred from organism to organism.Example:

It takes 100 kgs of plant materials (producers) to support 10 kgs of herbivoresIt takes 10 kgs of herbivores to support 1 kg of 1st level predator

100%

10%

10%

Energy PyramidDiagram that shows an ecosystem’s loss of energy.(p. 487)

Decreasing population & energy.

Trophic Levels Each step in a food chain or web (p. 484-5)

Sun >Producer; grass > Primary Consumer; rabbit (herbivore) > Secondary Consumer; coyote (carnivore) > Tertiary Consumer; scavenger (omnivore) >Decomposer; bacteria, fungi.

Consumers

• Herbivore - an organism that eats primarily plants.

• Carnivore - an organism that eats primarily other animals.

• Omnivore - an organism that eats both plants and animals.

Food Chain:

A diagram illustrating a simple feeding relationship among organisms. It shows how energy and matter are transferred through the environment.

Biomass vs. Biomagnification

• Biomass - the total weight of all living organisms in each trophic level. (primary, secondary, & tertiary consumers)

• Biomagnification- the process of contaminants becoming increasingly concentrated at each higher trophic level in a food chain or web.

THE FOOD WEB The food web shows that

ALL energy is transferred & recycled among organisms and their environments.

All organisms are important to maintain the balance of energy in a food web.

Food Web

Heterotrophs vs. Autotrophs

HeterotrophConsumers that rely on other organisms for their energy and food supply.

AutotrophAn organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer.

Food Web

Water cycle

• Evaporation• Transpiration• Precipitation• Runoff• Groundwater

Carbon cycle

• Combustion• Photosynthesis• Respiration• Decomposition• Fossil fuels

Nitrogen cycle

• Atmospheric nitrogen• Runoff• Fertilizers• Decomposition• Nitrogen fixing• Synthesis of amino acids

OrganismsAll organisms depend on one another and their environments for survival.