Energy Flow

From the Sun, Through an Ecosystem, Into Heat

Autotrophs / Producers Auto = Self-made

example: Automatic, Automobile

Troph = Eater / Food Example: trophy (prizes in competitions used

to be food!)

So, AUTOTROPHS make their own food. They produce their own food.

How? Photosynthesis!!!!

Heterotrophs / Consumers

Hetero = different Troph = food

Heterotrophs CANNOT make their own food, so they must eat other organism. They consume other animals.

Heterotrophs are ALL organisms that eat other organisms

They are herbivores, carnivores, omnivores, and detrivores. ALL of these animals cannot make their own food, and must eat other organisms (including plants) FOR food!

Decomposers

DECOMPOSERS are heterotrophs that eat dead things and in the process return nutrients to the soil.

DECOMPOSERS are always DETRIVORES Detrivore specifies that they eat dead things Decomposer specifies that they break down

dead things and return nutrients to the soil

What are some examples of DECOMPOSERS?

DECOMPOSERS

Bacteria

Fungi

Flies

Maggots

Hyenas

Dung Beetles

Worms

Mold

Primary, Secondary, Tertiary

Primary Consumers eat Autotrophs (plants)

Secondary Consumers eat Primary Consumers

Tertiary Consumers eat Secondary Consumers

Pop Questions

Are all consumers meat-eaters?

NO! Herbivores are consumers too

Are carnivores ever primary consumers?

NO! But, omnivores can be

Are herbivores always primary consumers?

YES!

Trophic Levels

Each step in the chain represents a TROPHIC LEVEL

A trophic level is an feeding step in the passage of energy and materials through an ecosystem

Energy Flow

Energy enters the ecosystem as Sunlight Sunlight is the One + Only + Ultimate

energy source

It is turned into food by autotroph (plants) However, plants only capture 1% of total sun /

energy Plants use this energy to grow, to reproduce,

to move (a little), and to keep themselves alive

Overall, plants use 90% of energy this way! So, only 10% of energy is passed on to the

next trophic level (whatever eats the plant)

10% Rule At every level, 90% of the energy received from

food is used to keep the organism alive.

For example, a zebra who eats grass only gets 10% of the energy from grass that the grass got from the sun.

Then, the lion who eat the zebra only gets 10% of the energy from the zebra that the zebra got from the grass. This makes sense! THE ZEBRA USES ENERGY

RUNNING AWAY FROM THE LION!!

Energy Pyramid

Pop Question!

The same holds true with Biomass

Biomass: Total amount of living tissue within a given trophic level (I am ___ lbs of human biomass)

Just like an energy pyramid, BIOMASS decreases as you go up trophic levels. And, the 10% Rule

applies! Energy is mass!

So, how much grass does it take you to

survive?Meat Eater:

Human Cow Grass Sun

150lbs x 10 (cow) x 10 (grass)

15,000 lbs

Vegetarian:

Human Vegetables Sun

150lbs x 10 (veggies)

1500 lbs

It’s better for the earth to be a vegetarian. Except…You may not be getting enough

PROTEIN!

Ok, let’s see how we’re doing

First, put a P (producer) or a C (consumer) next to the animals

Now, put a O (omnivore), H (herbivore), or C (carnivore) next to the animals too.

Now draw an energy pyramid (up to Tertiary Consumer) using any of those animals.