Lecture 2 Impact of Human Activities on Ecosystem Lisa Antoniacci Ph.D. Marywood University
Dec 25, 2015
Lecture 2Impact of Human Activities on Ecosystem
Lisa Antoniacci Ph.D.Marywood University
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
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
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
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
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
Deforestation
• Human activities strip woodlands of trees– Flooding – Landslides
– Increases atmospheric CO2
– Decreases atmospheric oxygen
• Deforestation– Removal of all trees from a large tract of land
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
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
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
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
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
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
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
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
ACTIVITY #1POLLUTION LAB
Using Kit: Water Pollutants and a Living Organism
Pre-Lab InstructionsPOLLUTION 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
Pre-Lab InstructionsPOLLUTION 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
Pre-Lab InstructionsPOLLUTION 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 conditions3. Place 1 drop of distilled water in 6 depression slides4. Add 1 drop of Bottle A and then 1 drop of living organism5. 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 result8. Repeat by adding 1 drop of each pollutant (B-F) to the remaining depression
slides and record results.
Pre-Lab InstructionsPOLLUTION 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
Pre-Lab InstructionsPOLLUTION LAB
Procedure – Part 2 (Synergy)
1. Place 1 drop of Pollutant B 4 depression slides2. Add 1 drop of Bottle C and then 1 drop of living organism to first slide3. 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 result6. Repeat by adding 1 drop of each pollutant (D-F) to the remaining depression
slides(containing a drop of B and record results.