I. Biomes (Chap ) - land ecosystems occurring over broad areas - combination of mountain, climatic, and current effects - similar types or organisms within biomes

A. Tropical rain forest 1. richest and most organismal diversity 2. about half of living species 3. often equatorial 4. slow to recover after disturbance - weak soil

B. Savannas 1. grasslands bordering the tropics - open landscape - some trees, mostly scattered 2. often transition between rain forest and desert

C. Deserts 1. often on continental interiors - many around 30˚ latitude 2. organisms adapted to little water - dry feces

D. Chaparral 1. near mid-latitude coastal areas 2. mild, rainy winters and long, hot, dry summers 3. dense, spiny shrubs with evergreen leaves

E. Temperate grassland (prairie) 1. more temperate than savannas 2. few trees 3. very fertile - important for agriculture

F. Temperate forests (broadleaf, hardwoods) 1. deciduous trees 2. loss of leaves decreases water loss during the winter 3. recover well after disturbance

G. Taiga 1. coniferous forests - evergreens with needle leaves 2. long, cold winters and short, wet summers - many familiar Montana wildlife - wolf, deer, bear, elk, moose 3. in coastal regions some are actually temperate rain forests

H. Tundra 1. open grassland 2. ground frozen (permafrost) - plant roots cannot get deep penetration 3. rain collects in bogs - permafrost and slow evaporation 4. grazing animals and some predators - musk ox, caribou, reindeer, arctic fox - mosquitoes can be overwhelming in summer

I. Elevation effect

II. Man’s Impact on Ecosystems (Chap 38) A. Habitat destruction B. Introduction of non-native species

C. Pollution 1. acid rain a. sulfur from burning coal - from tall stacks into upper atmosphere - Clean Air Act of 1990

b. nitric oxide from burning fossil fuels c. lowers pH of ecosystems - kills mycorrhizae

2. biological magnification a. PCBs (polychlorinated biphenyls) - industrial chemicals

b. DDT

D. Ozone layer 1. protective layer in the upper atmosphere a. O 3 b. shield for solar UV 2. CFCs (chlorofluorocarbons) - catalyze conversion of O 3  O 2 - ozone hole over the south pole

III. Greenhouse Effect A. CO 2 released from burning fossil fuels and wood B. Trapping heat  global warming

Well-known data:

Not-so well known facts: % of the atmosphere that is CO 2 = % of the atmosphere that is water vapor = 0 - 4% 0.05%

IV. Nuclear Alternative A. Relatively cheap and “clean” B. Must meet three criteria 1. safety 2. proper waste disposal 3. security