Biomagnification Lesson

Pesticides

What are they used for?• Chemical

substances used to kill insects that eat crops or cause disease

How do Pesticides end up in the environment?

1. Absorbed by crops2. Surface runoff into lakes and

rivers3. Vaporized into atmosphere;

returned by rainfall

Define bioaccumulation.

Persistent Organic Pollutants

Bioaccumulation= accumulation of substances (often chemicals) in an organism

Bioaccumulation

Normal process how organisms accumulate minerals and nutrients in our bodies (fats, carbs, etc.)Also how we store toxins (poisons) in our bodies

Biomagnification Activity

1. You have a card on your desk determining your trophic level.

2. Write down your trophic level where it says assigned organism in your table.

3. You are to “eat” the prescribed number of the organisms below you by finding the people who are the trophic level below you (producers must obtain water from the different water sources around the room).

Biomagnification Activity

4. Write down the amount of toxin (ppm) gained from each organism you eat. Add up the total in the column at the bottom. Only eat as many as the card tells you to.

5. When you are done, write your total ppm gained on the board under your appropriate trophic level. Then, have a seat and wait until everyone else if finished.

6. You can start on the DDT reading while you wait.

Example:

PRODUCER18 ppm

Consumes 20 gallons of water from 4 different

sources

SECONDARY CONSUMER

100 ppm

Eats 5 primary

consumers

Your Assigned Organism:

Organism Eaten Amount of Toxin Attained from Organism (ppm)

1

2

3

4

5

6

Total ppm:(Add up all ppm)

Total PPM Producer Primary Consumer

Secondary Consumer

Tertiary Consumer

1

2

3

4

5

6

7

AVERAGE:

What do we notice about the amount of toxin as we move up the food chain?

Biomagnification

Tendency of toxins to concentrate in organisms at higher trophic levelsDue to eating small organisms with small amounts of toxin present

DDT Reading

You have 10 minutes to read through the Case Study and answer the 6 questions.

We’ll discuss the answers in 10 minutes.