Download Chapters 3, 4, and 5 Notes Earth`s Resources

Name__________________________
Hour___________ Date____________
Chapters 3, 4, and 5 Notes
Earth’s Resources
Environmental Issues
Section 3.1/3.2 (pg. 86-91/pg. 92-97)
•
What is an issue?
It’s an idea of a problem or question on which
people have different viewpoints.
People have always used the Earth’s resources. We
compete for limited resources and this can cause
three main types of environmental issues that are
all interconnected.
- Population growth: improvements in
medicine, agriculture, and sanitation enabled
people to live longer and need more resources
- Resource use: anything naturally occurring
in the environment used by people is a natural
resource.
• Renewable resources are naturally replaced in a short amount of
time (ex. Sunlight, wind, and trees) but can be used up
• Nonrenewable resources are not replaced as they are used (ex. coal
and oil) because they are limited in supply
-Pollution: a change in the environment that has a negative effect on living
things
• Usually the result of an activity that benefits humans (electricity and
pesticides)
• Point source (sewage pipe) vs. nonpoint source (cars)
•
Approaches to environmental issues
– Choices must be made at personal, local, national, and global levels.
• Transportation, waste disposal, energy, emissions, food, clothing
•
We must understand how we interact with the environment.
– Environmental science is the study of natural processes that occur in
the environment and how humans can affect them.
– Information is used as part of decision-making process.
– Requires consideration of different points of view; balance between needs
of the people and needs of the environment.
•
Viewpoints on environmental decisions fall into three main categories:
– Development viewpoint: humans should be able to freely use and benefit
from all of Earth’s resources (economics - businesses, money, and jobs)
– Preservation viewpoint: all parts of the environment are equally
important, no matter how useful they are to humans (caretakers of nature
- beauty, comfort, and recreation)
– Conservation viewpoint: people should use resources from the
environment as long as they do not destroy these resources (balance Chapters 3, 4, and 5 Notes
8th Grade Science
1
•
development and for the future)
Costs and benefits of a decision are considered
– Can be measured in terms of money, scenic / habitat value, safety, shortand long-term effects.
– Ex. ANWR oil drilling
Natural resources are important because we depend on resources for
survival and development.
– Unfortunately, they are not equally available in all parts of the world.
– Sustainable use is one way that we can maintain resource use at a certain
quality for a certain amount of time.
– Measured through an ecological footprint, or the amount of land and
water used to meet resource needs and absorb waste
– Conservation is the practice of managing resources so that they last
longer; policies influenced by government and industry needs.
Types of Resources
Section 3.5 (pg. 108-117)
•
The number of different species in an area is called biodiversity.
– Difficult to measure because so much of the planet has yet to be
thoroughly explored.
– More than 1.7 million species have been identified
•
Biodiversity as a resource (economic) provides:
– Food
– Industrial products (raw materials)
– Medicine
• Pain killers, antibiotics, heart drugs, antidepressants, and anticancer
drugs
– Ecotourism
•
Biodiversity also provides value to the ecosystem.
– Recall that all species are connected to each other, if one changes others
will be affected also.
– Keystone species influence the survival of many other species, they often
keep the ecosystem in balance. Ex. Sea stars and mussels
•
Factors affecting biodiversity include:
– Climate: number of species increases from poles towards equator; tropics
contain over half of the world’s species - consistent temperature and
rainfall (continuous growing season)
– Area: large area contains more species
– Diversity of niches: lots of jobs that are filled by lots of different species
•
Types of Biodiversity
– Ecosystem: variety of habitats or communities
– Species: large # of species in biosphere
– Genetic: variety of genetic combinations of DNA, allows for better
Chapters 3, 4, and 5 Notes
8th Grade Science
2
adaptation to the environment (large gene pool)
Threats to Biodiversity
Extinction is when all members of a species are no longer found on Earth
- Natural or human causes
•
Habitat Destruction (Greatest Threat)
– Land development
– Habitat fragmentation: (Destruction)
• Split up habitat due to construction
• Isolates native species; reduces availability of
resources
•
Demand for wildlife products
– Human action (hunting or poaching – illegal killing) leads
to extinction and not all countries have protection laws
–
Endangered species - group of organisms near
extinction while threatened species can become
endangered in the near future
•
Pollution in water, air, soil
– Biological magnification: concentrations of a harmful
substance increase in organisms at higher energy
levels in a food chain/web
•
Exotic (non-native, invasive) species compete for resources or eat native
species
Protecting biodiversity
-
Protect either individual species or entire ecosystems
Use scientific and legal approaches
Captive Breeding mating of animals in zoos or wildlife preserves, young are
often released back into the wild (costly)
ex. California Condor (mid-1980’s only 10 in wild)
•
Laws and Treaties
– Endangered Species Act 1973 - U.S. law
– CITES 1973 - over 80 nations agree but hard to
enforce
•
Habitat Preservation
– Whole ecosystems protected
– Most effective way to preserve biodiversity especially if area is diverse and
large enough to support populations that live there
•
Challenges
– Requires people to change the way they earn a living or live their life
•
Chapters 3, 4, and 5 Notes
8th Grade Science
3
Other Types of Resources
- Sections 3.4, 4.1, 4.3, 4.4, 5.1, and 5.2
Section 3.4 (pg. 102-107)
1. Forest Resources (renewable): make houses, fuel, CO2 filters, food, habitat,
protection, erosion and flooding prevention, etc.
–
Deforestation: loss of forest, leads to erosion & loss of native
plant/animal species
•
Clear-cutting (stumps left) vs. selective cutting (mix left)
•
Could plant & harvest trees on tree farms to limit deforestation
and provide sustainable yield (how many can be harvested
without reducing future supply)
2. Fishery Resources (limited renewable): food
–
Over-fishing: slows natural replacement
–
Manage for sustainable yield by setting limits, laws for fishing
methods, developing aquaculture (raising aquatic animals for
consumption - can be destructive; i.e. waste), and finding new sources
(different fish).
Section 4.1 (pg. 128-133)
3. Land Resources: less than 1/4 of earth’s surface is dry land, and allows for life
(place to live), industry, & crops
•
Changed by:
– Agriculture (growing food , less than
1/3 of surface)
– Mining (removal of nonrenewable
resources)
• Strip mining - resources right
beneath the surface, expose soil
that may become eroded (blown
or washed away)
• Underground mining - requires digging tunnels (shafts)
– Development (settling on land by other resources and making buildings,
roads, bridges, dams, and more)
Protecting the Soil
– Soil is a complex system made up of living and nonliving things
– Absorbs, stores, and filters water
– Bacteria, fungi, etc. break down wastes and remains of other organisms
(recycle elements)
•
–
–
–
–
Soil structure (takes hundreds of years to form a few cm)
Litter - Very top level of dead leaves and grass
Topsoil - Mixture of rock fragments, nutrients, water, air, and decaying
plant and animal matter (plant roots)
Subsoil - Rock fragments, water, air, and little organic matter
Bedrock - rock that makes up the Earth’s crust (broken apart by freezing
Chapters 3, 4, and 5 Notes
8th Grade Science
4
•
and thawing, plant roots, chemicals from lichens, animals)
Poor soil management leads to:
– Soil erosion: wearing away of top soil by water & wind (prevent by strip
cropping, contour plowing, conservation plowing, windbreaks, and
terracing)
– Nutrient depletion: plants use more nutrients than
decomposers can replace, soil is less fertile (prevent
by allowing to go fallow, leave parts in the field, or
rotate crops)
– Desertification: extreme soil erosion over time
(caused by climate, overgrazing, and cutting trees)
•
Use land reclamation to restore area to a more natural, reproductive
state.
Section 4.3 (pg. 142-151)
4. Air Resources: to breathe!
Air is a mixture of nitrogen, oxygen, carbon dioxide, water vapor and other gases.
(Remember the cycles - prevent air from running out!)
Solid particles and gases released into the air are emissions. If it has harmful
effects by changing the atmosphere, it is air pollution. Can be point
(smokestack) or nonpoint (automobiles) sourced. Some are natural
(animals).
–
Smog: a mixture of chemicals in the air; reacts with sunlight to form
ozone, a toxic form of oxygen
• From: auto exhaust & industry
• Leads to respiratory problems
• Temperature inversion - a layer of warm air prevents the rising air
(full of pollutants) from escaping into the upper atmosphere instead it concentrates near the Earth’s surface
–
Acid Rain
• Caused by release gases from burning fossil fuels (cars, factories)
making nitrogen oxides and sulfur oxides
• Gases combine w/ moisture in air; causes precipitation pH to drop
below 5.6
• Acid rain dissolves soil nutrients, rusts cars, and can affect stone and
metal in buildings
• Kills plants, aquatic life, causes lung disease
• May be able to reverse effects by adding lime (base)
–
Indoor Air Pollution
• Negative effect because of chemicals or other substances mixed with
air - dust, pet hair, asbestos, cleaning supplies, glue, paints,
cigarette smoke
• Carbon monoxide - colorless and odorless gas formed from not
completely burning wood, coil, oil or natural gas
• Radon - colorless and odorless gas that is radioactive (formed
Chapters 3, 4, and 5 Notes
8th Grade Science
5
naturally underground)
The Ozone Layer - protective atmosphere about 30 km above the Earth’s surface
(good).
It cycles - when ozone (O3) absorbs ultraviolet (UV) radiation, it splits into an
oxygen molecule and oxygen atom.
•
Ozone Hole caused by CFC’s (Chlorofluorocarbons) pg.148-149
–
Hole allows UV radiation (ultraviolet) to reach the earth
•
Why are UV rays bad?
–
Cause cancer
–
Eye damage
–
Decrease resistance to disease
•
Does NOT cause global warming
•
•
•
Greenhouse Effect - energy from the sun strikes the Earth’s surface,
changing to heat. H2O vapor, CO2, and other gases act like windows and
trap this heat and keep us warm
Global Warming - increase in CO2 from burning fossil fuels can cause
temperature of Earth to rise (3-8 degrees C)
–
Possible effects: melt polar ice, raise ocean levels, alter climates,
change weather, influence agriculture practices
Predict climate change - use computer models to test theories in a short
amount of time using information from ocean research, emissions data,
clouds, forest research
Section 4.4 (pg. 152-159)
5. Fresh Water Resources: Only 3% of the Earth’s water is fresh that can be
used for drinking and watering crops; 3/4 of this is in ice form
•
The water supply is renewable (water cycle) but its not always evenly
distributed or used faster than replaced
Problem: pollution
1.
Chemicals (fertilizers and pesticides from agriculture –
poisonous/cause algae to block sun: oxygen depletion)
2.
Sewage (has disease-causing organisms)
3.
Industry and mining (chemical and metal wastes)
4.
Sediments (rocks, silt, and sand –block sun, cover organisms)
5.
Heat (thermal pollution)
6.
Oil and gasoline
Solutions: clean gas/oil spills, treat sewage (pg. 156), reduce
pollutants
- wetlands are a natural filter, bacteria for oil, recycling wastes &
Chapters 3, 4, and 5 Notes
8th Grade Science
6
general conservation
Section 5.1(pg. 178-185)
6. Energy Resources (nonrenewable): fuel is a substance that provides a form
of energy - such as heat, light, motion, or electricity - as a result of a
chemical change. Long time to form (500,000,000+ years)
•
Fossil fuels - energy-rich substances formed from the remains of once
living organisms, made of hydrocarbons (combustion combines the C and H
with O to form CO2 and H2O releasing energy as heat and light)
Types of fossil fuels:
1.
Coal (solid from plants; US has most of this; easy to transport;
can increase pollution, and cause disease in workers)
2.
Oil (liquid from small animals, algae, and protists; found in holes
in the underground sandstone or limestone; 1/3 of energy produced in
world comes from oil; called crude but can be refined into
petrochemicals to make plastic, paint, etc.)
3.
Natural gas (gas that is a mixture of methane and other gases;
located above oil deposit; can be compressed into liquid; lower pollution
than other types of fossil fuels)
Section 5.2 (pg. 186-195)
Renewable energy sources:
1.
Solar energy (heat and light)
2.
Wind energy (indirect solar energy - differences in temperature
and pressure)
3.
Hydroelectric power (indirect solar energy - flowing water)
4.
Tidal energy (gravity pull of sun and moon)
5.
Biomass fuels (ethanol, wood – formally living things to make
alcohol and methane gas)
6.
Geothermal energy (heat water using energy from magma)
7.
Hydrogen power (pass electric current through water)
•
Nuclear Energy - converting matter into energy; E =mc2
Types of nuclear reactions:
1.
Fission - split nucleus into two smaller nuclei (U-235 large,
unstable nucleus) and hit it with a neutron
mass is now less; missing mass is energy (which changes water
to steam and drives generators)
produces three neutrons to hit
Alternatives/Solutions

Integrated pest management
other U-235 nuclei and continue

Use of renewable energy sources
the reaction
wind, water, solar

Planting trees to replace those used
Problems: meltdown of fuel rods
Limits deforestation
leads to explosion and

Conservation

Recycling
radioactive materials escaping;
waste disposal
Why go to all this trouble?
2.
Fusion - Hydrogen 3 (one proton and two neutrons) and Hydrogen
2 (one proton and one neutron) combine to form Helium and an
extra neutron and energy
Chapters 3, 4, and 5 Notes
8th Grade Science
7
-
hard to control this reaction (15 mil deg C and lots of pressure)
Chapters 3, 4, and 5 Notes
8th Grade Science
8