Energy Flow thru Ecosystems

Without the Sun there would be no life on earth.

Energy Facts

The sun is the major supplier of the earth’s energy.Yet only 0.1% of the sun’s energy is used by living organisms.Plants use 1/2 of the energy they receive and store the other as organic compounds.Producers  are autotrophic organisms (as a green plant) that accumulate biomass by converting sunlight to energy storing molecules.Energy cannot be recycled, it flows through the ecosystem. Most of the energy released is lost in the form of heat.

The amount of solar energy collected by all producers in an ecosystem is called primary productivity.

Which ecosystem do you suppose has the highest primary productivity: desert, forest, swamp, tundra, grassland?

Actually, even the energy of a campfire comes from the sun. How?

Sun Photosynthesis Wood Campfire

Even the energy from a hydroelectric dam comes from the sun. How?

Sun water evaporates rain river hydroelectric dam

Even the energy captured by a windmill comes, from the sun. How?

Sun unequal heating winds windmill

More about Energy Flow

Decomposers are organisms that obtain their energy from dead organic matter. Bacteria/FungiScavengers are organisms that typically feed on refuse or carrion. Coyote/Eagle Organism eat organism at different feeding levels. These levels are called trophic levels.Ecosystems are made of many trophic levels.The amount of useable energy that is transferred from trophic level to trophic level is approx. 10%.

Energy Pyramids (Trophic Levels)

The lowest trophic level of the pyramid represents the producers and contains the most energy.The second level represents the primary consumers, also called 1st order. A 90% decrease in useable energyThe third level or secondary consumers will have 10% of the energy from the level below to use.

Heat

0.1%

100%

10%

1%

= Total Energy

= Useable Energy

Thinking time.

All first order consumers are also called what?

Herbivores

Let’s Practice

How many trophic levels are present?

5

Determine the amount of useable energy for the different trophic levels.

Level 2: 36 J

Level 3: 3.6 J

Level 4: 0.36 J

Level 5: 0.036 J

Pyramid of Numbers

Carnivore populations are smaller in comparison to the rest of the ecosystem.

They require more food to sustain their lives than the lower organisms.

10

200

100,000

200,000Producers

Herbivores

Carnivores

Carnivores

Food Chain

The simplest feeding arrangement in an ecosystem.Producers (autotrophs) are always at the base of the chain.The food chain may vary in length.Example: Grass - cow - Human.Ex.: plankton – insect – minnow – small fish – large fish - osprey

Food Webs

Many food chains interacting with each other.

The arrow always points away from the organism being eaten to the organism doing the eating.

Shows the movement of energy and matter in an ecosystem.

A more accurate description of all feeding relationships in an ecosystem.

Nutrient Cycles

The sun’s energy drives most nutrient cycles.

Much of the earth’s chemical nutrients are tied up in many life forms.

The earth’s nutrients are finite, so they must be recycled.

Examples: Hydrologic, Carbon dioxide, and Nitrogen Cycles.

Hydrologic Cycle

Key terms: Evaporation: Liquid water changing state to a gas.Condensation: Gaseous water changing state to a liquidPrecipitation: Water dropping from the sky.Transpiration: Loss of water from plants.Run off: Water not being absorbed into the ground.Ground water. Water found under ground

Carbon Cycle

Key Terms:Photosynthesis: Autotrophs capture the sun’s energy in organic compounds.Respiration: Organisms releasing the stored energy from organic compounds.Combustion: Burning of organic compounds.Carbonic Acid: An acid formed from carbon dioxide and water.Calcium Carbonate: Chemical found making up bone and shells.

Nitrogen cycle

Plant and animal wastes decompose, adding nitrogen to the soil.Bacteria in the soil convert those forms of nitrogen into forms plants can use.Rain storms contribute atmospheric nitrogen (78%) through rain drops that reach the soil.Legumes, such as soybeans, alfalfa and clovers, are plants that can convert atmospheric nitrogen into plant-usable nitrogen. Factories that produce nitrogen fertilizers add nitrogen to the soil when farmers and gardeners "feed" their crops.

The Flow of Energy

Since plants capture the sun’s energy and store it in food, they are said to be producers.The amount of solar energy collected by all producers in an ecosystem is called primary productivity.Animals that receive their energy directly from plants are called primary consumers (herbivores).Consumers that feed on primary consumers are called secondary consumers (carnivores).Energy flows from the sun to the producer, then to the primary consumer, then to the secondary consumer, etcTertiary consumer is the top order consumer in a food pyramid.

Review

* Producers - capture the sun’s energy and store it in food.* Primary Productivity - amount of solar energy collected by all producers in an ecosystem* Primary Consumer – animals that receive their energy directly from plants* Secondary Consumers – Consumers that feed on primary consumers* Tertiary consumer - is the top order consumer in a food pyramid.