energy flow and trophic levels in ecosystems food webs pyramid

Main energy source for life on Earth

Sunlight.

Autotrophs

Organisms that capture energy from sunlight or chemicals to make their own food; also known as producers.

Photosynthesis

The process of using light energy to convert carbon dioxide ($CO_2$) and water ($H_2O$) into oxygen ($O_2$) and carbohydrates.

Main land producers

Plants.

Main aquatic producers

Algae in freshwater and upper ocean layers, and photosynthetic bacteria in tidal flats and salt marshes.

Chemosynthesis

The process of using chemical energy from inorganic compounds to produce carbohydrates.

Heterotrophs

Organisms that rely on other organisms for their energy and food supply; also known as consumers.

Herbivores

Consumers that feed exclusively on plants.

Carnivores

Consumers that feed exclusively on animals.

Omnivores

Consumers that feed on both plants and animals.

Detritivores

Consumers that feed on plant and animal remains and other dead matter.

Decomposers

Organisms, such as bacteria and fungi, that break down organic matter.

Direction of ecosystem energy flow

A one-way pathway from the sun or inorganic compounds to producers, and subsequently to consumers.

Food chain

Series of steps in which organisms transfer energy by eating and being eaten.

Food web

Links all the food chains in an ecosystem together.

Trophic level

Each Step in a food chain or food web

First trophic level

Producers.

Second, third, or higher trophic levles

Consumers and they depend on the trophic level below it for energy.

Ecological pyramid

A diagram showing the relative amounts of energy or matter contained within each trophic level.

Energy pyramid

A diagram showing the relative amount of energy available at each trophic level.

Rule of energy transfer

Only about $10$ percent ($10\text{\%}$) of the energy in a trophic level transfers to the next level, with the rest lost as heat.

Biomass

The total amount of living tissue within a given trophic level.

Biomass pyramid

A diagram representing the total amount of living tissue and potential food available at each trophic level.

Pyramid of numbers

A diagram showing the relative number of individual organisms at each trophic level.

3 different types of ecological pyramids

Energy pyramid, Biomass pyramid, Pyramids of Numbers