130 likes | 912 Views
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 crops 2. Surface runoff into lakes and rivers
E N D
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 crops • 2. Surface runoff into lakes and rivers • 3. 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 storetoxins (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: PRODUCER 18 ppm SECONDARY CONSUMER 100 ppm Eats 5 primary consumers Consumes 20 gallons of water from 4 different sources
Biomagnification • Tendency of toxins to concentrate in organisms at higher trophic levels • Due 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.