Transcript Human Impacts

Human Impacts
Ecology Unit
Learning Goal 5
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Earth as an Island
• All organisms that live on the Earth share
a limited resource base and depend on it
for their long-term survival.
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A resource for shelter and space
A resource for food supply
An energy source
A source of recreation
A major source of medicines
Natural resource for industrial products.
Resources
• Renewable
Resources that
can regenerate or
have a virtually
unlimited supply.
Nonrenewable Resources
• Resources that cannot be replenished by
natural processes.
– Fossil Fuels
• Coal
• Oil
• Natural Gas
– Entire Ecosystems (sometimes)
Natural Areas
• Critical habitat for many plants and
animals is disappearing.
– If there is no place to find food and shelter
organisms are forced to relocate or die.
Categories of Biodiversity
• Ecosystem Diversity
The variety of habitats that
exist on Earth.
• Species Diversity
The number of different
species in the biosphere.
• Genetic Diversity
Different forms of genes
present within a species.
Ecosystem Services
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Solar Energy
Oxygen Production
Nutrient Recycling
Purification of Air and
Water
• Pollination for food
production
• Soil fertility and
erosion prevention
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Species at Risk
• Factors leading to endangerment or
extinction.
– Habitat Destruction
– Invasive Species
– Overexploitation
– Disease
– Pollution
• Eutrophication
Occurs in aquatic environments when excessive
nutrients are added resulting in a bloom of algae
that robs the water of oxygen.
Species at Risk
• Extinct: A species that no longer exists.
• Endangered: A species facing imminent
extinction.
• Threatened: a species likely to become
endangered if limiting factors are not
reversed.
California Condor
• As recently as the early 1800s, the California Condor occupied
mountains along the Pacific coast from British Columbia to northern
Baja California. By the mid-twentieth century, the population
declined to a small population in south-central California. Through
captive breeding, California Condors have been reintroduced to the
coastal mountains of south-central California and the Grand Canyon
area of northern Arizona. Condors prefer mountains, gorges, and
hillsides, which create updrafts, thus providing favorable soaring
conditions.
Endangered Species
Air quality
• Air Quality is affected by pollutants that
come from the combustion of fossil fuels.
– Vehicles, homes, power plants, smelters, and
other industries.
• Smog can affect our health.
Acid Rain
• Acid rain is caused by the chemical
conversion in the atmosphere of SO2 and
NO2 into nitric acid and sulfuric acid.
• Those are now monitored and controlled.
Water Quality
• Water is threatened by pollutants that
enter the bodies of water.
Biological Magnification
• Concentration of a harmful substance increase
in organisms at higher trophic levels in a food
chain.
• For example, if in one day a little fish eats 1,000
plankton and a whale eats 1,000 little fish, the
whale is ingesting all the toxins that were in a
million plankton!
– (1,000 x 1,000 = 1,000,000)
• Example
– DDT and Bald Eagles
Ozone Depletion
• Ozone absorbs most of the UV radiation from
the sun.
– UV radiation may lead to many health concerns.
• Depletion of the ozone has been linked to the
uses of CFCs.
• Today the use of most CFCs has been banned.
• CFC molecules can stay in the atmosphere as
long as a century.
• We have yet to see the effect of the CFC ban.
Climate Change
• Average global temperatures at the
Earth’s surface have increased 0.6 – 1.2oF
since the late 1900’s.
• Effect of Climate Change
– Change in weather patterns.
– Increase in severe weather.
– Melting of the polar ice caps.
– Change in habitat for organisms.
– Change in entire ecosystems.
Greenhouse Effect
What Can People Do?
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Use mass transit
Use vehicles that get good gas mileage
Use energy-efficient appliances.
Recycle
Conserve our resources.
Clean up our messes.
Preserve habitat
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We can do better!!!
The End