bellringer: third box on bell-ringer page

1. What is the source of all energy in this ecosystem ? (WHERE DOES IT ALL COME FROM)

2. How does energy get from the source to the hawk?

BELLRINGER: Third Box on Bell-ringer Page

• Be able to explain energy transfers among organisms using food chains and ecological pyramids.

Today’s Objective:

Can be found in the book: Pg. 46 - 50

• The ultimate source of the energy for life is the sun.

• Autotrophs are our link to the energy from the sun. All other organisms depend on autotrophs.

• An organism that uses light energy (mostly plants) to make food is a producer, or autotroph.

The Producers: Autotrophs

• Autotrophs use the sun’s energy to manufacture food energy in a process called

photosynthesis.

• An organism that cannot produce it’s own food energy and has to eat/consume other organisms for energy is

a heterotroph.

The Consumers: Heterotrophs

• There are different types of heterotrophs.

The Consumers: Heterotrophs

• A heterotroph that feeds only on

plants (autotrophs) is an

herbivore.

• Some heterotrophs just eat other heterotrophs- these are carnivores.

The Consumers: Heterotrophs

• Some heterotrophs eat both heterotrophs and autotrophs.

They are called omnivores.

The Consumers: Heterotrophs

• Scavengers eat animals that have already died.

• They don’t actually kill for food, but they only eat dead heterotrophs

The Consumers: Heterotrophs

• Some organisms, such as bacteria, fungi, and some worms are decomposers.

The Consumers: Heterotrophs

• Decomposers break down the complex compounds of dead and decaying plants and animals into simpler molecules that can be

more easily absorbed.

The ultimate source of energy is…….

This energy goes to……

Autotrophs

How do heterotrophs get their energy?

By eating autotrophs…..And by eating the

heterotrophs that ate autotrophs…..

Who do you think is getting more energy?

• Food energy flows through an ecosystem from producers to consumers in a chain…

• Matter (like water and carbon) gets recycled.

• Energy does not….it changes and is replenished everyday by the sun.

• In a food chain, nutrients and energy move from

• autotrophs to

• heterotrophs and, eventually, to

• decomposers.

• A food chain is a simple model that scientists use to show how energy moves through an ecosystem.

• The arrows in a food chain show the direction of ENERGY FLOW.

berries → mice → black bear

The Flow of Matter and EnergyFOOD CHAINS

• Most food chains consist of only two, three, or four transfers.

The Flow of Matter and EnergyFOOD CHAINS

• Only about 10% of the energy is transferred at each feeding step…..

berries → mice → black bear1000 kcals

100 kcals

10 kcals

This is why a bear would have to eat a lot of mice….

• If only 10% is transferred to the consumer, what happens to the rest of the energy?

LEFT BEHIND AND GIVEN OFF AS HEAT ENERGY

• Each feeding step in a food chain is called a trophic level.

• The first CONSUMER in a food chain is called a primary or first-order heterotroph.

• The first-order heterotroph eats autotrophs.

• A second order heterotroph is an organism that feeds on a first order heterotroph.

• A third order heterotroph or tertiary is an organism that feeds on a second order heterotroph.

• REMEMBER: a food chain represents only one possible route for the transfer energy through an

ecosystem.

• An ecological pyramid is another way to show a food chain.

1. The autotroph is always at the bottom of the pyramid

2. As you go up the pyramid, you go higher in the trophic levels

Grasses (3000)

Grasshoppers (250)

Birds (25)

Fox (1)

This pyramid is a pyramid of

NUMBERS.

This pyramid shows ENERGY LOSS.

Pyramid of Energy

Heat

Heat

Heat

Heat

0.1% Consumers

1% Consumers

10% Consumers

100% Producers

Parasites, scavengers, and

decomposers feed at each

level.