1. Unit 7-1 Notes Mr. Hefti – Pulaski Biology

3. Ozone Depletion ► Ozone Depletion ► What is it? Thinning of ozone layer Shield of gases 20-50 km above Earth’s surface that absorb UV radiation from sunlight

4. OD ► OD ► What causes it? CFCs (chlorofluorocarbons) break apart ozone molecules CFCs were formerly used to make: – Foam – Coolants – Propellants for aerosol cans

6. OD ► OD ► Why is it bad? UV exposure causes: – Sunburns – Skin cancer – Damage to eyes – Disrupted growth patterns of producers in food webs – Genetic mutations

7. OD ► OD ► What can be done about it? Ban CFCs [worldwide]

9. Water Pollution ► Water Pollution ► What is it? Contamination to: – Streams – Lakes – Underground water (aquifers) – Bays – Oceans All organisms require water

10. WP ► WP ► What causes it? Major water pollutant categories: – Chemical – Biological – Physical materials – Thermal

12. WP ► WP ► Why is it bad? Survival impossible in presence of toxic chemicals or harmful microorganisms Polluted water causes people to become ill or develop defects

13. WP ► WP ► What can be done about it? Clean Water Act (1972) – outstanding legislation Sewage treatment Discourage careless dumping through fines Limit erosion