i. biomes (chap 34.8-17) - land ecosystems occurring over broad areas - combination of mountain,...

I. Biomes (Chap 34.8-17)- land ecosystems occurring over broad areas- combination of mountain, climatic, and current effects- similar types or organisms within biomes

A. Tropical rain forest1. richest and most organismal diversity2. about half of living species3. often equatorial4. slow to recover after disturbance

- weak soil

B. Savannas1. grasslands bordering the tropics

- open landscape- some trees, mostly scattered

2. often transition between rain forest and desert

C. Deserts1. often on continental interiors

- many around 30˚ latitude2. organisms adapted to little water

- dry feces

D. Chaparral1. near mid-latitude coastal areas2. mild, rainy winters and long, hot, dry summers3. dense, spiny shrubs with evergreen leaves

E. Temperate grassland (prairie)1. more temperate than savannas2. few trees3. very fertile

- important for agriculture

F. Temperate forests (broadleaf, hardwoods)1. deciduous trees2. loss of leaves decreases water loss during the winter3. recover well after disturbance

G. Taiga1. coniferous forests

- evergreens with needle leaves2. 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. Tundra1. open grassland2. ground frozen (permafrost)

- plant roots cannot get deep penetration3. rain collects in bogs

- permafrost and slow evaporation4. 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 destructionB. Introduction of non-native species

C. Pollution1. acid rain

a. sulfur from burning coal- from tall stacks into upper atmosphere- Clean Air Act of 1990

b. nitric oxide from burning fossil fuelsc. lowers pH of ecosystems

- kills mycorrhizae

2. biological magnificationa. PCBs (polychlorinated biphenyls)

- industrial chemicals

b. DDT

D. Ozone layer1. protective layer in the upper atmosphere

a. O3b. shield for solar UV

2. CFCs (chlorofluorocarbons)- catalyze conversion of O3 O2- ozone hole over the south pole

III. Greenhouse EffectA. CO2 released from burning fossil fuels and woodB. Trapping heat global warming

Well-known data:

Not-so well known facts:% of the atmosphere that is CO2 =% of the atmosphere that is water vapor = 0 - 4%

0.05%

IV. Nuclear AlternativeA. Relatively cheap and “clean”B. Must meet three criteria

1. safety2. proper waste disposal3. security