Download Essentials of Biology

Essentials of Biology
Sylvia S. Mader
Chapter 32
Lecture Outline
Prepared by: Dr. Stephen Ebbs
Southern Illinois University Carbondale
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
32.1 Resources and Pollution
• Resources are the materials that meet the basic
needs of living organisms.
– There is a finite supply of nonrenewable resources.
– Renewable resources are continually produced and
are not finite.
• Pollution occurs when the release of by-products
from resource utilization alter the environment in
an undesirable way.
Land
• Humans require land for habitation, industry,
and agriculture.
• Human use of land has negative impacts.
– Human activities contribute to the erosion and
pollution of beaches.
– The use of land located near deserts can lead to
desertification.
– Deforestation of land can also lead to desertification
and a loss of biodiversity.
Land (cont.)
Land (cont.)
Land (cont.)
Water
• Humans alter the distribution of water in the
environment with dams and aquifers.
• Dams have several negative impacts.
– The natural course of rivers is disrupted, damaging
estuaries.
– Water is lost by evaporation and seepage.
– Salt and agricultural runoff can affect the water.
– Sediment can build up, reducing the effectiveness of
the dam.
Water (cont.)
• Water redistribution and/or removal can have
other consequences for the environment.
– Subsidence can occur when groundwater is removed.
– Groundwater removal can also cause saltwater
intrusion.
• Water conservation is becoming increasingly
important as the availability of potable water
supplies decreases.
Food
• Modern agricultural techniques have had
several negative effects.
• Monoculture has increased the
susceptibility of crops to disease and
insect herbivory.
• Heavy use of fertilizers and pesticides has
polluted the environment.
Food (cont.)
• Over-irrigation has depleted water
supplies.
• Energy consumption during agriculture
has drawn from finite fossil fuel supplies.
• Agriculture has contributed to soil loss.
Food (cont.)
• Other efforts to enhance the human food
supply have had mixed results.
• The Green Revolution and genetic
engineering have produced high
productivity plants that often require high
inputs of water and nutrients.
Food (cont.)
• Livestock production has
provided protein for the
human diet but has also
been energy intensive
and a source of pollution.
• Fishing has also provided
protein but is depleting
the populations of some
fish.
Energy
• Nuclear power provides approximately 6% of the
world’s energy.
• Nuclear power can be dangerous and produces
radioactive wastes that persist for thousands of
years.
• Most of the world’s energy (approximately 75%)
is provided by nonrenewable fossil fuels.
• The burning of these fossil fuels introduces
pollutants into the environment.
Fossil Fuels and Global Climate
Change
• Carbon dioxide, a by-product of fossil fuel
production, is a greenhouse gas that many
believe is causing global climate change.
– Temperatures are expected to rise.
– The polar ice caps will melt.
– The melting ice caps will cause sea levels to
rise.
Fossil Fuels and Global Climate
Change (cont.)
Renewable Energy Sources
• There are five main forms of renewable
energy.
– Wind power
– Hydropower (hydroelectric power)
– The geothermal energy (heat from beneath
the Earth’s surface)
– Solar energy
– Solar-hydrogen energy (extraction of
hydrogen from water by electrolysis)
Renewable Energy Sources
(cont.)
Minerals
• Minerals are nonrenewable resources that
are often mined from the environment.
– Fossil fuels are considered minerals.
– Nonmetallic minerals include phosphate, sand,
and gravel.
– Examples of metallic minerals include
aluminum, copper, iron, nickel, and precious
metals.
Other Sources of Pollution
• Heavy metals are a threat to human health
and ecosystem health.
• Synthetic organic compounds can be toxic
and can influence global climate change.
• These toxic compounds can accumulate in
food chains through biological
magnification.
Other Sources of Pollution
(cont.)
Other Sources of Pollution
• Industrial wastes pollute the environment
by releasing potentially hazardous
compounds.
• Release of raw sewage can contribute to
human disease and pollute water sources.
32.2 Biodiversity
• Biodiversity can be described as the variety of
life on the Earth.
• Currently, biodiversity is decreasing due to rapid
extinction of species.
• Extinction is caused by a variety of factors.
• Conservation biology is an effort to protect
biodiversity.
32.2 Biodiversity (cont.)
Direct Values of Biodiversity
• Biodiversity can provide value directly to
humans.
– Medicinal value through pharmaceuticals and
natural compounds
– Agricultural value as a food source
– Consumptive use value for commercial
products
Indirect Values of Biodiversity
• Biodiversity can provide indirect value.
– Contribution to the biogeochemical cycling of
nutrients in the environment
– Disposal of wastes (decomposition)
– Natural filtration and regeneration of water
sources
– Reduction of erosion
– Regulation of climate
– Ecotourism
Indirect Values of Biodiversity
(cont.)
Working Toward a Sustainable
Society
• A sustainable society can provide the needed
resources and protect biodiversity.
• Current human society is not sustainable.
– More land is used for human purposes, rather than
left as natural ecosystems.
– Agriculture relies on nonrenewable resources.
– Too much agriculture is devoted to livestock.
– There is too much reliance on nonrenewable fossil
fuels and minerals.
Working Toward a Sustainable
Society (cont.)
Working Toward a Sustainable
Society (cont.)
• A sustainable society would have the
following characteristics.
– Renewable energy sources would be used to
provide energy.
– Heat and waste materials would be used
efficiently.
– There would be maximal recycling of all
resources.
Working Toward a Sustainable
Society (cont.)