Energy Flow through a Food Chain

ENERGY FLOW

Autotrophs vs.

Heterotrophshttp://legacy.owensboro.kctcs.edu/gcaplan/bio/notes/BIO%20Notes%20E%20Photosynthesis.htm

http://legacy.owensboro.kctcs.edu/gcaplan/bio/notes/BIO%20Notes%20F%20Respiratioin.htm

Energy Flow (Trophic Levels)

• Producers- make their own food

• Consumers- get energy from consuming producers

Producers

• Producers- capture energy from sunlight or chemicals and use the energy to produce food.

• Producers are autotrophs- they make food from their environment

2 main types of autotrophs

• One type gets energy from the sun-by photosynthesis

• Another type gets energy without light- by chemosynthesis

Consumers

• Consumers are heterotrophs- get energy from other organisms

Types of Consumers

• Herbivores- eat only plants• Carnivores- eat animals• Omnivores- eat both plants and animals• Detritivores- eat dead matter (plants and

animals)

Feeding Relationships• Energy flows through an ecosystem in one direction

from:– 1. the sun or inorganic compounds– 2. To autotrophs (producers)– 3. To heterotrophs (consumers)– Decomposers get energy from decomposing dead organisms

Food Web- A network of feeding relationships.

(More realistic that a food chain)

Food Chain- a series of steps in which organisms transfer energy by eating or being eaten.

Food Web

They can become very complex!

Trophic levels

• Each step in a food chain or a food web is called a trophic level.– Producers are the first trophic

level– Consumers are the second,

third, or higher trophic level

• Each trophic level depends on the one below for energy

Energy Pyramid

• Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off)

• Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level

Biomass Pyramid

• Biomass- the total amount of living tissue within a given trophic level.

• A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.

Energy Losses

• Energy transfers are never 100 percent efficient

• Some energy is lost at each step

• Limits the number of trophic levels in an

ecosystem

• Energy flow is a one way path! (not a cycle)

All Heat in the End• At each trophic level, the bulk of the energy

received from the previous level is used in metabolism

• This energy is released as heat energy and lost to the ecosystem

• Eventually, all energy is released as heat