Human Influences on the Living World

Pollution

•Everything is linked in biosphere• If damaged done to one ecosystem, it can affect

another ecosystem• Ex. Japan’s nuclear power plant

•Air Pollution• Major problem in cities• Increase number of health issues (e.g. asthma)

Mexico City

“Brown air city”

•Water pollution• Not enough water to dilute substances especially

with the amount of people in the world• Better sewage systems but still have issues

Portland Sewage System

• Many substances get washed into streams (e.g. fertilizers)

•Biological magnification

• substances (e.g. pesticides) do not break down quickly and accumulates in fat tissue of organisms

• substance then move up the food chain by being eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans

Bald Eagle eggs affected by DDT

Acid Precipitation

•Pollution from industry enters atmosphereand combines with water vapor creating acid rain

• Harms surrounding ecosystems and biodiversity found there

Ex. Black Forest in Germany

Global Warming

•Greenhouse effect• Naturally helps maintain Earth’s climate• Acts like a thermostat, by trapping heat reflected by

from Earth’s surface• Greenhouse gases are CO2, CFCs, NOx, CH4

•Global warming is correlated with the increased levels of CO2

• Causing profound change in temperature• Increasing 1-4˚ C each year• Changes rain patterns, sea levels, areas for agriculture

The Ozone Hole• Ozone layer absorbs about 97-99% of sun’s high

frequency UV rays

The Ozone Layer

•1920’s increase use of Chlorofluorocarbons(CFCs)

• Source of CFC: refrigerator coolant, AC, aerosol cans

Loss of Biodiversity

•Alarming rates of extinction in recent years

Why is biodiversity important?

1. Organisms have adapted to live together in a community

• Change one of the organisms, it changes the community

• Ex.: if predators are removed from an area, the other organisms may reached carrying capacity faster

2. Brings stability to ecosystem

• A pest could destroy an entire corn field where as it would have a much more difficult time doing so to a tropical rain forest

•An analogy•Each species in a community are like rivets in an airplane

•Rivets hold an airplane together, as more rivets are removed from an airplane, the more likely the plane will fall apart.

Why do humans care about biodiversity?

•We depend on other organisms for our needs

• Many plant and algae species contribute to the production of oxygen

• Diverse diet (from zucchini to shrimp)• Helps farmers/breeders make stronger (e.g. drought

resistant)• Materials (construction, clothes, etc…)• Pharmaceuticals (e.g. penicillin)

• Possible cure for cancer and HIV

Causes for Loss of biodiversity

•Habitat loss• Single most important cause of extinction• Other factors that come from habitat loss are

destruction, pollution, human disruption, habitat fragmentation

Midwest land fragmentation Animal crossing in Netherlands

•Species overexploitation• Species that are over hunted or harvested

Mahogany treesBison

•Examples of animals hunted into extinction

Great Auk Thylacine (marsupial wolf)

•Introduction of species (aka invasive species)

• Species intentionally or accidentally introduced into an area• Gardens, boats, cars

• Since there are no natural predators to keep populations in check

Reducing Pollution

•Factors to be taken into consideration when trying to reduce pollution

• The cause/source of pollution• Economics behind source

•Ways tried to reduce pollution• Antipollution Laws

• Example: Clean Air Act• Pollution Taxes

Preserving Nonreplaceable Resources

•Renewable Resources• is quickly replaced or recycled by natural processes in a time

frame that makes it useful for human consumption or use• Examples: cotton, wood, wind, water

•Nonrenewable (nonreplaceable) Resources • that cannot be readily replaced by natural means on

a level equal to its consumption• Example Petroleum products

•Top Soil• Humus – fertile portion of the soil

where crops are grown• Takes hundreds of years do develop • Degradation due to soil erosion, wind

erosion, over-tilling

•Groundwater• Soil acts like a natural filter and water percolates

through• Underground reservoirs developed during the melt of

the last ice year (over 12,000 years ago)• Problems faced are over pumping and pollution

Curbing the Population Growth

•Human population is exponentially growing• Population is doubling almost every 60 years Causes

for population growth• Control over food• Treatment for diseases• Better sanitation• Shelter improvement

Even though growth rate has been decreasing

Decline thought to be due to: family planning efforts, increase economic power, empowering

women, better education

•Consumption disparity• Wealthiest countries make up about 20% of world’s

population• responsible for 86% of the world’s consumption of resources• Also responsible for over 50% of the wastes

Preserving Endangered Species

•Habitat restoration• Restore plants/animals in area to natural habitat

• Example restoration of prairies• Removable of introduced species

• Example Himalayan blackberry • Cleanup and Rehabilitation

•Captive Propagation• Involves direct intervention of natural population in

threat of extinction• Examples Peregrine Falcon, Black-footed ferrets

• Sustaining Genetic Diversity• Decrease in genetic diversity leads to many problems within

species• Such as increase disease and other health problems

• Solution: moving individuals between populations

•Preserving Keystone Species• A species that plays a crucial role within an

ecosystem• Their removal has large impact on ecosystem• Examples: wolves in Yellowstone, Flying Fox, sea

otters

•Conservation of Ecosystems

• Preserving larger areas of habitat

• Smaller, isolated habitats lose species more rapidly

• Keep habitat intact is best way to preserve biodiversity as opposed to individual species

Finding Cleaner Sources of Energy

•Burning fossil fuels has increased the amount of CO2 in atmosphere

• Remember that CO2 holds in heat from leaving atmosphere

• Result: Climate temperature is increasing

•Switching to alternative sources of energy• Nuclear, wind, water, solar, ethanol