Biology I: Energy Flow Through an

Ecosystem (part 2)

Food Chains, Food Webs, Energy Pyramids

Agenda – Tues. Oct. 4, 2011

Warm-Up

Lesson

Wrap-Up (Identifying food chains)

Wrap-Up (Identifying producers, consumers, decomposers)

Homework Worksheet

Today’s ObjectivesI will explore energy flow within an

ecosystem.

I will define: ecosystem, herbivores, omnivores, carnivores, food chain, food web, energy pyramid.

I will trace food chains within a food web.

I will classify organisms as: producers, consumers, or decomposers.

Warm-Up1.What do decomposers do?

2.If you ate chicken that previously ate grass, what type of consumer would you be?

3.Where does energy flow ultimately begin?

What is an Ecosystem?

An Ecosystem is all of the living organisms and non-living environment found in a particular place

What is an Ecosystem?

Example: a pond or aquatic ecosystemLiving Things: fish, turtles, algae, insects, bacteriaNon-Living Things: physical and chemical

properties of the pond like the amount of oxygen in the pond and its pH

Trophic LevelEach feeding level in an ecosystem

Each level of a food chain or food web

First Trophic Level: made up of only producers

Trophic LevelSecond Trophic Level:

made up of primary consumers

Herbivores: primary consumers that mainly eat plants

Examples: rabbits and grasshoppers

Trophic LevelThird Trophic Level:

made up of secondary and tertiary consumers

Omnivores: consumers that eat both plants and animals

Examples: humans and squirrels

Trophic Level

Carnivores: consumers that mainly eat other animals

Examples: lions and sharks

Food ChainThe flow of energy from the sun to

producers to primary consumers then to higher order consumers can be shown in a food chain.

Food ChainShows only one path for the flow of

energy in an ecosystem.

Food WebEcosystems have many different types of

food chains.

A food web shows how many different types of food chains are connected.

Food webs show the feeding relationships in an ecosystem.

Example Food Web

Energy PyramidEnergy Pyramids show the energy loss

between trophic levels in an ecosystem.

The flow of energy:

radiant energy (sunlight)

chemical energy (stored in plants)

kinetic energy and heat loss (created as consumers feed on each other)

Energy PyramidThe amount of available energy

decreases up the energy pyramid.

Energy Pyramid

Most of the “lost” energy is released as heat into the environment.

Each trophic level contains fewer organisms.

Why does this make sense?

18

How Many Chains are in this web?

copyright cmassengale

Identify the Producers, Consumers, and Decomposers