Final Exam Thursday 7-10 pm here Non-cumulative Same format Covers all lectures since Exam 2 200 of 1000 points Sample ?s/Answers on web under Exam 3 Use.

Final Exam

Thursday 7-10 pm here

Non-cumulative

Same format

Covers all lectures since Exam 2

200 of 1000 points

Sample ?s/Answers on web under Exam 3

Use lecture outlines, book + PP to study.

QUESTIONS?

levels of ecological systems:

Ch 26: Global Ecology

A. Human activities threaten local ecological processes.

1. Overexploitation

2. Introduce exotic species

3. Habitat conversion

4. Irrigation

5. Fertilizer --> eutrophication

1. overexploitation of marine animals…

1. overexploitation by grazers that leaves the land unproductive…

Shifting cultivation = sustainable if on a longrotation cycle (with low population density).

2. Introduction of exotic species…

Purple loosestrife Zebra mussels

Spread of zebra mussels in waterways

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Plenty of Invasive Species on Continents

•Great Lakes - zebra mussels, gobies, sea lamprey

•Starlings, house sparrows•mosquito fish, gypsy moth

•Kudzu, water hyacinth•garlic mustard, purple loosestrife, salt cedar, tumbleweed

Nile perch vs. cichlid fish in Lake Victoria

3. Via habitat conversion…

And via bad land use practices… 1% of topsoil is eroded each year.

4. via irrigation…

5. via overfertilization ---> eutrophication + anoxia…

B. Toxins accumulated in the environment… 1. Acids (e.g. Sulfuric acid drainage from coal mines)…

and acid rain from coal-burning industries.

2. heavy metals…

3. organic compounds

4. radiation

C. Atmospheric pollution threatens on a global scale…

1. Ozone (O3) + UV radiation

a. at surface

b. Ozone in upper atmosphere CFCs and ‘black hole’

Ozone depletion has increased over time…

Less ozone---> > UV ---> > damage to DNA

2. GH gases --> ‘greenhouse effect’

CO2 emissions from coal and oil

…and from clearing/burning vegetation

What is your ‘ecological footprint’?

• For every kilojoule of food energy we eat, 10 kilojoules of fossil fuel energy is required to put that food on your table.

• How many hectares to produce enough biological-produced fuel (ethanol) to meet our energy needs?• 10.7 hectares (23 football fields!)/person• Globally only 1.7 hectares of land available for each of earth’s 6 BILLION people…• How many resources do you use?• 30 X as many as a person in India…

Ecological footprints of some nations already exceed available ecological capacity.

Exponential growth of the human population

What is the carrying capacity of the globe?

Doubling time of human since 1 AD

When Nt/No = 2 = ert

So ln 2 = rt, t = ln2/r

0-1650 = 1650 yrs to double r = .00041650-1850 = 200 yrs r = .00351850-1930 = 80 yrs r = .00871930-1975 = 45 yrs r = .01521975-2010 = 35 yr r = .0.92So both N and r are increasing…

Our survival now depends on our becoming the ‘ecological species’ and taking our proper place in the ‘Economy of Nature’.