Chapter 3 Section 2 Energy Flow

Producers…

• Sunlight is the main energy source for life on Earth.– Less than 1% of the sun’s energy that reaches

Earth is used by living things.– Not all organisms obtain energy from the sun.• Some types of organisms rely on the energy stored in

inorganic chemical compounds.• Mineral water from underground or hot springs.

Producers…

• In fact only plants, some algae, and certain bacteria can capture energy from sunlight or chemicals and use that energy to produce food.

• Autotrophs are organisms that use sunlight or chemicals to produce its own food.– They are also called producers. – Producers are essential to the flow of energy

through the biosphere.

Producers…

• The best-known autotrophs are those that harness solar energy through a process known as photosynthesis. – Photosynthesis is the process that uses light

energy to convert carbon dioxide and water into oxygen and energy rich carbohydrates such as sugars and starches.

– Sunlight + CO2 + H2O O2 + C6H12O6

Producers…

• Life without light…– Chemosynthesis is the process where organisms

use chemical energy to produce carbohydrates.• Occurs in several types or bacteria that represent a

large portion or autotrophs.• Occurs in remote places on Earth like volcanic vents on

the deep ocean floor and hot springs in Yellowstone park, or even tidal marshes.

Consumers…• Heterotrophs are organisms that rely on other organisms

for their energy and food supply.– They are also called consumers.– Different heterotrophs are:

A. HerbivoresA. eat plants only.

B. CarnivoresA. Eat animals

C. OmnivoresA. Eat both plants and animals

D. DetritivoresA. Eat dead matter.B. Also called decomposers

Feeding Relationships…

• Energy flows through an ecosystem in one direction, from the sun or inorganic matter to autotrophs and then to various heterotrophs.– Food Chains are a series of steps which organisms

transfer energy by eating and being eaten– Food Webs link all the food chains in an ecosystem

together.

Feeding Relationships…

• A Trophic Level is each individual step in a food chain or food web.– Producers make up the first trophic level.– Consumers make up the second, third, or higher

levels.• Each consumer depends on the trophic level below it.