Ecology
Lake Tahoe Community College
Fall Qtr.
Instructor: Sue Kloss
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Ch. 23– Global Ecology and Economic Development
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Global Ecology
I. The atmospheric envelope and global warming
A. Atmosphere =
B. Atmosphere helps keep earth surface warm by acting like a blanket and trapping heat
1. greenhouse gases
2. gases trap IR heat and reradiate to earths surface(Fig. 23.2)
3. bc of global circulation, pollution produced in 1 part of earth eventually get everywhere
II. Human activity and global nitrogen cycle
A. agriculture and industrial processes, we’ve manipulated the global nitrogen cycle on a huge scale
B. Changes in land cover threaten biodiversity
C. Inconvenient Truth
Ecology and Economic Development
A. Ecological Processes hold the key to environmental policy
1. Three key functions of ecosystem processes are cycling of nutrients, info transfer and energy flow
2. Restorative processes may be physical, but often they are biological.
B. Human activities threaten local ecological processes
1. pretty much all human activity has environmental consequences
2. sometimes the link is not a direct one
3. Overexploitation
4. introductions of exotic species
5. habitat conversion
6. Irrigation
7. Fertilization and Eutrophication
C. Toxins have accumulated in the environment - interfere with normal function of organisms - several classes:
1. Acids
2. Heavy Metals - mercury, arsenic, lead, copper, nickel, zinc and other heavy metals are toxic in
sufficient quantity. Usually introduced as mining refuse into water or soils (fig. 26.10 - copper mine, UT)
lead comes from gasoline, which is still leaded in most of the world
3. Organic Compounds - used as pesticides ; accumulate in other parts of the food chain, though, and
do damage
4. Radiation - nuclear power wastes and accidents (3 mile island, Chernobyl), war, weapons, and
medicine
D. Atmospheric Pollution
1. ozone layer disruption, UV radiation in southern hemisphere (fig. 26.12)
2. CO2 and greenhouse gases - methane etc. (Fig. 26.13)
Study Questions/Lesson Objectives
1. What key 3 main ecological processes are intimately linked to human activities and why?
2. How are these processes threatened by human actions? Provide examples.
3. Give examples of direct human influence on ecosystem function, and indirect human influence on ecosystem function.
4. Describe 5 large classes of human activities (eg. Overexploitation, etc.) that disrupt ecosystems. For each class of
activities, provide some actual effects on ecosystems and examples.
5. Toxins have accumulated in the environment - describe sources of these toxins, their effects on organisms and
ecosystems, and examples.
6. Describe various types of atmospheric pollutants, their sources and effects on the biosphere.
7. Describe 6 different types of activities that humans are undertaking to mitigate effects of harmful activities on the
environment.
8. Think globally, act locally.
9. Travel responsibly, enjoy the amazing world we live in.