1. Lecture 2 Impact of Human Activities on Ecosystem Lisa Antoniacci Ph.D. Marywood University

2. 18.5 Human Effects on the Biosphere The increasing size of the human population and its increasing industrialization have far-reaching effects on the biosphere Effects range from extinction of individual species to global climate change

3. Increasing Species Extinctions Humans are increasing the rate of species extinctions by degrading, destroying, and fragmenting natural habitats, by overharvesting species, and by introducing exotic species

4. Increasing Species Extinctions Endangered species –Faces extinction in all or part of its range Threatened species –Likely to become endangered in the near future Endemic species –Evolved in one place and is found nowhere else

5. The Global Impact of Human Activities Human activities threaten entire ecosystems –Desertification –Deforestation –Air pollution and acid rain –Water pollution –Trash in aquatic ecosystems –Air pollution and the ozone hole –Greenhouse gases and global warming

6. Desertification Poor agricultural practices turn grasslands or woodlands into deserts –US Great Plains (the Great Dustbowl) –Sahara Desert Desertification –Conversion of grassland or woodlands to desertlike conditions

7. Deforestation Human activities strip woodlands of trees –Flooding –Landslides –Increases atmospheric CO 2 –Decreases atmospheric oxygen Deforestation –Removal of all trees from a large tract of land

8. Pollution Human activities generate pollutants that kill animals and damage ecosystems Pollutant –Natural or man-made substance released into the environment in greater than natural amounts, and that damages the health of organisms

9. Acid Rain Acid rain –Rainfall contaminated by acidic pollutants –Burns trees, kills fish, leaches nutrients from soil Caused by pollutants that combine with water vapor in the atmosphere to form acids –Sulfuric acid from sulfur dioxides from coal- burning power plants and factories –Nitric acid from nitrogen oxides from vehicles and power plants that burn gas and oil

10. Other Sources of Water Pollution Pollution from point sources may be identified; dealing with pollution from nonpoint sources is more difficult –Industrial chemicals and heavy metals –Oil from vehicles –Runoff of fertilizers, pesticides, herbicides, and animal wastes –Sewage and excreted prescription drugs –Sediments

11. Some Results of Water Pollution Bioaccumulation –Concentration of toxins such as mercury as they move up through the food chain Eutrophication –Nutrient enrichment by sewage and fertilizers, resulting in toxic algal blooms or oxygen depletion Turbidity –Clouding of water by sediment runoff, blocking sunlight and choking animals

12. The Trouble With Trash Human activities generate plastics and other trash that kill animals and damage ecosystems –Chemicals from buried trash contaminate groundwater –Wastes dumped or washed into the ocean damage marine ecosystems –Plastics can persist more than 100 years

13. Air Quality Pollution from airborne particles damages respiratory systems of humans and animals –Burning of fossil fuels and industrial processes Some pollutants have global effects –CFCs cause thinning of the ozone layer –Rising levels of greenhouse gases contribute to climate change

14. The Ozone Hole Ozone is a pollutant near the ground, but depletion of the ozone layer is a global threat caused by the use of CFCs –Global agreement to phase out CFC use Ozone layer –Atmospheric layer with a high concentration of ozone that prevents much ultraviolet radiation from reaching Earth’s surface

15. Global Climate Change Climate change caused by rising concentrations of greenhouse gases is another global threat –Results in extremes in rainfall patterns and drought, increased hurricane intensity Global climate change –Global warming and other changes in the current climate and weather patterns

16. ACTIVITY #1 POLLUTION LAB Using Kit: Water Pollutants and a Living Organism

17. Pre-Lab Instructions POLLUTION LAB  Determining the effects of water pollutants on a living organism  Examining 6 known water pollutants  Regulatory agencies control pollutant dumping and concentrations in water….. BUT worry about Biological Magnification  Also need to assess positive synergy between pollutants

18. Pre-Lab Instructions POLLUTION LAB Procedure  Gather all materials (working in groups of 2-3)  6 pollutants labeled A, B, C, D, E, F  Depression slide  Plastic pipettes  Distilled water  Microscope

19. Pre-Lab Instructions POLLUTION LAB Procedure – Part 1 1.Prepare control by placing 2 drops of distilled water in depression slide. Then add 1 drop of organism 2. Use microscope to observe organism in the control conditions 3. Place 1 drop of distilled water in 6 depression slides 4. Add 1 drop of Bottle A and then 1 drop of living organism 5. Start timer and observe the organism under the microscope. 6. Record amount of time it takes to lose ability to swim (form coils) 7. Wait 5 minutes – if no changes in movement record a negative result 8. Repeat by adding 1 drop of each pollutant (B-F) to the remaining depression slides and record results.

20. Pre-Lab Instructions POLLUTION LAB Procedure – Part 1 Bottle A – Silver Nitrate Bottle B – Mercury Nitrate Bottle C – Nickel Nitrate Bottle D – Lead Nitrate Bottle E – Aluminum Nitrate Bottle F – Copper Nitrate

22. Pre-Lab Instructions POLLUTION LAB Procedure – Part 2 (Synergy) 1.Place 1 drop of Pollutant B 4 depression slides 2. Add 1 drop of Bottle C and then 1 drop of living organism to first slide 3. Start timer and observe the organism under the microscope. 4. Record amount of time it takes to lose ability to swim (form coils) 5. Wait 5 minutes – if no changes in movement record a negative result 6. Repeat by adding 1 drop of each pollutant (D-F) to the remaining depression slides(containing a drop of B and record results.