Levels of OrganizationFood Chains, Food Webs,

and the Transfer of Energy

Unit 6

Bell Ringer 03-16-15

Give an example of the following:

Producer:

Primary Consumer:

Secondary Consumer:

Tertiary Consumer:

Population

• All of the individuals of a species in a specific area at a certain time.

• Members of a population compete for food, water, space, and mates; for example, wildebeest’s in Kenya.

Communities All the different populations in a specific area at a

certain time. For example, all of the wildebeests, zebras, and

trees at the watering hole are part of the same community.

Some of these interactions involve the obtaining and use of food, space, or other environmental resources.

Ecosystem

One or more communities in an area and the abiotic factors, including water, sunlight, oxygen, temperature, and soil.

Abiotic factors non living parts of environment

(soil, air, light and temperature, water)

Biotic living or once-living organisms of environment

1. Autotrophs

A groups of organisms that can use the energy in sunlight and convert into food

Autotrophs are also called Producers because they produce all of the food that heterotrophs use

Without autotrophs, there would be no life on this planetEx. Plants and Algae

2. Heterotrophs

Organisms that do not make their own food.

Another term for Heterotroph is consumer because they consume other organisms in order to live. Ex. Rabbits, Deer, Mushrooms

Consumers

3. Scavenges – feed on the tissue of dead organisms (both plants and animals)

Ex. – Vultures, Crows, Shrimp

4. Herbivores – eat ONLY plants Ex. – Cows, Elephants, Giraffes

5. Carnivores – eat ONLY meat Ex. – Lions, Tigers, Sharks

6. Omnivores – eat BOTH plants and animals Ex. – Bears and Humans

Consumers7. Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers

Ex. – Bacteria and Mushrooms

Transfer of Energy When a zebra eats the grass, it does not

obtain all of the energy the grass has (much of it is not eaten)

When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)

8. The Law of 10% - Only 10% of the energy from one trophic level is transferred to the next.

Bell Ringer 03-17-15Give an example of the following terms:

Abiotic:

Biotic:

Autotroph:

Heterotroph:

Trophic Levels

Energy moves from one organisms to another when it is eaten

9. Trophic Levels: Each step in this transfer of energy is known as a trophic level. The main trophic levels are producers,

consumers, and decomposers

But Why 10%? We can examine this further by constructing a

pyramid of energy, which shows rates of production rather than standing crop.

Let’s use an ocean environment as an example: Algal populations can double in a few days, whereas

the zooplankton that feed on them reproduce more slowly and might double in numbers in a few months, and the fish feeding on zooplankton might only reproduce once a year.

The amount of organisms in one trophic level effects how many/how much energy there is in the next tropic level.

Some of the energy is lost to heat produced when they decompose.

10. Food Chains The energy flow from one trophic level to the

other is know as a food chain. A food chain is simple and direct It involves one organism at each trophic level

Primary Consumers – eat autotrophs (producers)

Secondary Consumers – eat the primary consumers

Tertiary Consumers – eat the secondary consumers

Decomposers – bacteria and fungi that break down dead organisms and recycle the material back into the environment

12. Ecological Pyramid An ecological pyramid shows the

relationship between consumers and producers at different trophic levels in an ecosystem.

They also show the relative amounts of energy or matter contained at each trophic level.

The Pyramid shows which level has the most energy and the highest number of organisms

Videos

Energy Pyramids

The following food chain locations should be represented:

Intertidal zone - possible organisms: rock algae, barnicles, starfish, moray eel

Open ocean zone - possible organisms: photoplankton, zooplankton, krill, blue whale

Land zone - possible organisms: Your choice Another zone of your choice

Draw each organism in the correct location on its energy pyramid. Color the organisms you have drawn. Label each organism in all pyramids. You may only use humans on one energy pyramid. Cut, fold, and tape your pyramid to form a four-sided

pyramid.

Create your own!

Analysis: How did the organisms vary with each of your four energy

pyramids? Compare your pyramid with a that of a friend's pyramid.

What similar organisms did you both use? How were your energy pyramids different from each

other?

Ecological Pyramid

1. Which level has the most energy?2. Which level has the most organisms?3. Which level has the least organisms?4. Which level has the least energy?

Food Chain

11. Food Web

Most organisms eat more than JUST one organism.

When more organisms are involved it is known as a FOOD WEB. Food webs are more complex and involve

many organisms.

S.N. Food Web Arrows

Notice that the direction the arrow points the arrow points in the direction of the energy transfer.

Food Web