Chapter 6 Human impact 6 1 Ecosystems provide

Chapter 6 Human impact 6. 1 Ecosystems provide us w/ “services” Recycling nutrients clear air & water O 2 food soil & more

Human activities affecting biosphere: Hunting & gathering- few demands Agriculture- ~11, 000 ya Industry- factories & machines (~200 ya) Urban development- waste & pollution

Traditional→modern agriculture: Monoculture-large fields planted with same crop every year Green revolution-fertilizers & monoculture to increase world food supply

6. 2 Environmental services are either renewable or nonrenewable Renewable resources-can be replenished Ex: some trees or H 2 O

Nonrenewable resources- can’t be replenished by natural processes Ex: fossil fuels, old forests

Sustainable development-using natural resources w/o depleting them Ex: using insects instead of pesticides to control pests

LAND RESOURCES Land can be permanently damaged if not managed properly Crops grow best in a mixed soil (sand, clay, rock pieces, & humus) Good soil is made by plant/soil interactions over a long time

Long plant roots hold soil in place & prevent erosion from wind & water Plowing removes these roots

Farmers can use contour plowing to reduce erosion Desertification- farming, overgrazing & drought turn productive lands into deserts

http: //www. youtube. com/watch? v=w 9 Rxnu. Bi. Fbg

FOREST RESOURCES Forests– O 2, clean water, nutrients, clothes, shelter, & medicine Deforestation-causes erosion Erosion- wearing away of soil by H 2 O or wind How can we use sustainable development in forests?

FISH RESOURCES Overfishing- big problem How can we sustain our fish? Aquaculture-raising aquatic animals for food

Air resources Smog-mix of chemicals (brown haze) in the sky; {cars & industry} Pollutant-harmful material that enters biosphere via land, air, or water

Acid rain- nitrogen and sulfur compounds in the air; burning fossil fuels form acids when mixed with H 2 O vapor Damages plants, releases other bad chemicals into biosphere

Freshwater resources Drinking, cleaning, crops, & other Forests & wetlands purify water we must protect them

Water damaged by: Chemicals Sewage Industry waste

6. 3 Biodiversity-total variety of all organisms in biosphere

Ecosystem diversity-includes the variety of habitats, communities, & ecological processes in biosphere

Species diversity-number of different species in biosphere (~1. 5 million spp. so far) Genetic diversity-total of all diff. forms of genetic info on earth

Why is biodiversity so important? Threats to biodiversity Extinction- species disappears from all or part of its range Endangered species- in danger of extinction

http: //www. youtube. com/watch? v=ZTTEdew. T 1 x. U

Habitat fragmentation-development that splits ecosystems into pieces Remaining pieces are “biological islands”

Page 152 in book Introduced/invasive speciesnonnative plants & animals can take over HOW? ?

Video on Burmese pythons http: //archives. nbclearn. com/portal/site/k-12/search

http: //video. nationalgeographic. com/ video/animals/amphibiansanimals/frogs-and-toads/toad_cane/

Biological magnificationconcentrations of a harmful substance ↑’s as trophic levels ↑ Ex: mercury, DDT

Mercury in fish http: //archives. nbclearn. com/portal/site/k 12/search

Conservation-wise management of natural resources What little things can you do to conserve biodiversity?

6. 4 Ozone layer-b/w 20 -50 km above earth is a high concentration of ozone gas O 3

On ground ozone is a pollutant ozone layer absorbs UV CFC’s (chlorofluorocarbons) caused big hole CFC’s were banned in late 1980’s

http: //video. nationalgeographic. com/video/ne ws/environment-news/antarctica-ozone-vin/

Global warming- ↑ in average temperature of biosphere What can we do?

http: //video. nationalgeographic. com/video/environment/globalwarming-environment/glacier-melt/

Video: Education | A Global Warming Warning | Watch Nature Online | PBS Video

Solutions: Alternative fuels– made from biomass Biodiesel- is made from vegetable oils & animal fats. Biodiesel can be used as a fuel for vehicles in its pure form Ethanol- (also propanol & butanol)-- most commonly worldwide; made by the action of microoraganisms & enzymes through the fermentation of sugars or starches or cellulose from corn, wheat, sugarbeets, etc. . Algal-This oil-rich algae can be processed into biofuels, with the dried remainder further reprocessed to create ethanol Fungal- isolate lg amts of lipids from single-celled fungi and turn it into biofuels in an economically efficient manner

Alternative/renewable energy 1. Wind power- renewable & sustainable Pro’s: clean, cheap once it is set up, abundant, used anywhere Cons’: kills birds/bats, need open space & constant wind, noise, ↑ ground tm

http: //video. pbs. org/video/2173872043/

2. Solar-renewable & sustainable; no greenhouse gas emission Pro’s: clean, abundant, quiet, efficient, low operating cost Con’s: expensive to start, not always sunny, need lots of space

http: //video. nationalgeographic. com/video/environment/energyenvironment/solar-cooking/

3. Hydroelectric- renewable & sustainable Pro’s: low pollution, safe, reliable, flexible, low upkeep Con’s: damage to ecosystem, expensive, droughts, limited

http: //video. nationalgeographic. com/video/ne ws/environment-news/yangtze-ride-wcvin/

4. Geothermal- renewable & sustainable Pro’s: no CO 2, no fuel needed, limitless, reliable Con’s: uses H 2 O, high initial cost, difficult, far from where it’s needed

http: //archives. nbclearn. com/portal/site/k-12/search Geothermal power: using earth’s heat to heat homes

5. Hydrogen- renewable & sustainable Pro’s: no CO 2, abundant, efficient, quick Con’s: not enough stations, availability, hard to separate H

http: //archives. nbclearn. com/portal/site/k 12/search Is hydrogen the fuel of the future?

6. Nuclear (fusion)- renewable Pro’s: clean, limit, low cost, less, little waste Con’s: expensive to build, need high temperature, hard to contain, waste disposal

http: //archives. nbclearn. com/portal/site/k 12/search Nuclear energy reconsidered: zero greenhouse gas, but deadly waste