Food Web and Trophic Energy Notes

Directions: Fill out your paper using the information found in this document

Food Chains and Food Webs

• Every living organism has to get its energy from somewhere. We show this transfer of energy with food chains and food webs

Interdependence • Every species is linked in an ecosystem and

relies (depends) on the others for survival

• Plants provide food, shelter, and nesting sites for other organisms. For their part, many plants depend upon animals for help in reproduction (bees pollinate flowers, for instance) and for certain nutrients (such as minerals in animal waste products). All animals are part of food webs that include plants and animals of other species (and sometimes the same species).

Feeding Relationships

• Energy flows in one direction, from the Sun to autotrophs (plants) and then to various heterotrophs (consumers).

Example:

SUN Plants Consumers

To draw a food chain, make sure to draw the arrows pointing to where the energy is

going

The arrows show where the energy goes to

The Food Chain • The food chain has 4 basic parts:

- The Sun - Producers - Consumers - Decomposers

Fill out the four boxes of the food chain using the information in the

next slides

The Sun • Provides energy for everything in the world

Mr. Shimko’s students are so

bright I have to wear my sunglasses

Producers • Plants- make their own food through

the process of photosynthesis

• Contain the most energy that’s why veggies are so good for you to eat!!!!

Categories of Consumers

• There are three main categories of consumers: - Primary consumers: herbivores or omnivores (eat producers) - Secondary consumers: carnivores or omnivores that eat primary consumers - Tertiary consumers: carnivores or omnivores that eat secondary consumers

Different types of consumers in action

Decomposers

• Break down dead matter into important gases that are released back into the ground, air or water

Food Webs

• A complex network that links all of the food chains in an area.

Food Webs Practice

1. Which organisms are the top carnivores? 2. What organisms eat toads? 3. What organisms do the foxes eat? 4. Which organisms have the lowest biomass? 5. What organisms have the highest biomass? 6. What are the producers? 7. What are the primary consumers?

1. Which organisms are the top carnivores? 2. What organisms eat toads? 3. What organisms do the foxes eat? 4. Which organisms have the lowest biomass? 5. What organisms have the highest biomass? 6. What are the producers? 7. What are the primary consumers?

Foxes, Hawks, Owls, Snakes

Snakes

Rabbits, Squirrels, Mice, birds

Foxes, Hawks, Owls, Snakes

Plants

Plants

Rabbits, Squirrels, Mice, Seed-eating birds, and herbivorous insects

8. Another bird population, which foxes can eat, enters this food web. What would happen to the fox population? 9. What would happen to the populations of the herbivorous insects and the predaceous insects if the spiders were eliminated by insecticide? 10. What would happen to the snake population if the toads went extinct? 11. What would the snakes try to do to survive?

8. Another bird population, which foxes can eat, enters this food web. What would happen to the fox population? 9. What would happen to the populations of the herbivorous insects and the predaceous insects if the spiders were eliminated by insecticide? 10. What would happen to the snake population if the toads went extinct? 11. What would the snakes try to do to survive?

Population would increase

Both insect population would probably increase

Population would decrease

Find something else to eat

Does all of the energy transfer?

Trophic levels describe the transfer of energy through a food web

Only about 10% of the energy is passed on to the next trophic level (because energy is used for living).

IN OTHER WORDS…As you get higher on the food chain, less energy is transferred from consumer to consumer, meaning MORE FOOD is needed to provide energy needs.

FAST FACT

• Owls must eat ¼ of their own body weight every night to survive!

See how the amount of energy decreases with each trophic level?

1. Where does the energy for an ecosystem come from?

1. Where does the energy for an ecosystem come from?

2. Where is most of the energy in an ecosystem?

2. Where is most of the energy in an ecosystem?

Is energy the only thing that transfers through a food chain?

• BIOMAGNIFICATION refers to the higher amount of a toxic chemical in animals higher on the food chain.

Because the chemicals don’t break down, they accumulate in organisms, and as

organisms are eaten, their chemicals are transferred to their

predator.

Eventually, the top carnivores have lots of

the pollutant.

3. Which organisms most likely have the most energy in this ecosystem?

3. Which organisms most likely have the most energy in this ecosystem?

4. Which organisms most likely have the highest amount of toxins in this ecosystem?

4. Which organisms most likely have the highest amount of toxins in this ecosystem?

Last Steps: 1) Turn your paper over

and complete the practice sheet on the back

2) Turn your paper in at the front of the class

3) Take the quiz on Socrative