Humans in the Biosphere
Chapter 6
Changing Landscape
• Activities affect environment
• Relationship between resources
and sustainable use
Effect of Human Activity
• Living on Island Earth
– We affect environment when:
• Obtain food
• Eliminate waste products
• Build places to live
– Humans impact regional and global environments:
• Agriculture
• Development
• Industry
Which impact natural resources such as soil, water and the
atmosphere.
Effect of Human Activity
Agriculture
– Dependable supply of food that can be stored for
future use
– Monoculture-clearing large areas of land to plant
a single highly productive crop annually (soybean)
• Efficient sowing , tending, and harvesting of crops
• Providing food for nearly 7 billion people-impacts
natural resources
– Fertilizer production and Farm machinery-consume large
amounts of fossil fuels.
e.g.-Canola Oil
Soybean
Effects of Human Activity
• Development
– Dense human communities produce lots of
wastes.
• Not disposed correctly they affect air, water and soil.
– Consumes farmland
– Habitat fragmentation
Effects of Human Activity
• Industrial Growth
– Conveniences utilize a great deal of energy to
produce and power
– Energy comes from burning fossil fuels such as
coal, oil and natural gas (emits greenhouse gases90 % of US emissions)
– Past-dumped waste directly into air, water and soil
Sustainable development
• Goods-things that can be bought and sold and
have value in terms of dollars and cents.
• Services-processes or actions that produce
goods.
• Ecologically-these are goods and services
produced by ecosystems that benefit the
human economy.
What type of goods and
service?
Ecosystem Goods and Services
• Many natural and free of charge
– Breathable air
– Drinkable water
• In environment cant provide-society must
spend money to produce
– E.g. many places drinkable water is free; source
polluted or damages and water quality falls-must
pay for water treatment to be safe.
Renewable and Nonrenewable
Resources
Renewable
• Can be produced or
replaced by healthy
ecosystem.
• E.g. southern white pine
that can grow back when an
old tree dies or is cut down.
Nonrenewable
• Natural processes cannot
replenish these goods
within a reasonable amount
of time.
• E.g. fossil fuels (formed
from buried organic
material over millions of
years) ; when depleted they
are gone.
Sustainable Resource Use
• Conscious Way to use resources
• Provides for human needs while preserving
the ecosystem that produce natural resources
– No harm to soil, water or climate
– Flexible enough to survive environmental stresses
(droughts, floods, heat waves, etc.)
– Human economic systems-more than just enable
people to survive-must help situation.
Using Resources Wisely
Soil Resources
• Important objects that rely on soil
– Grain in cereal
– Wood in home
– Pages of textbook
• Healthly soil supports agriculture and forestry.
Topsoil- mineral- and nutrient- rich
portions of soil
• GOOD
– absorbs and retains moisture
– allows draining
– rich organic matter and nutrients
• Renewable Resource
– Properly managed
– Healthy soil can take centuries to forms but be lost
quickely
1930s drought
• Badly eroded once-fertile soil of Great Plains
– Thousands lost jobs and homes
– Became a desert w/ dry soil- aka “dust bowl”
– Cause-conversion of prairie land to cropland in
way that left soil vulnerable to erosion (wearing
away).
Soil Erosion
• Removal of soil by water or wind
• Worse- land plowed and left barren b/w
plantings.
• No roots to hold soil-easily washed away
• Badly eroded-organic materials and minerals
that make soil fertile are carried away.
Desertification
• Dry climates-farming, overgrazing, seasonal
drought and climate change can turn farmland
to desert.
– Great Plains is an example
– 40% of Earth’s land is considered at risk
Desertification Risk
Deforestation
• Loss of forest
• Forests value
– Wood
– Hold soil in place
– Protect quality of water
– Absorb CO2
– Moderate local temperature
Deforestation
• ½ of world’s old-growth forests (never been
cut) lost
• Temperate areas-forest can regrow after
cutting; centuries for succession
• Tropics-forest DO NOT grow back after logging
• Old-Growth forest usually considered nonrenewable.
Deforestation can:
• Leads to severe erosion
• Change local soils and microclimates in a way
prevent regrowth of trees
– E.g Tropical Rain Forest• Soil is thin and decomposition quick b/c of high heat
and humidity.
• Soil ok for few years
• Then becomes wasteland; harsh conditions prevent
regrowth
Soil use and sustainability
• Minimize erosion through careful
management of both agricultural and forestry
– Leaving stems and roots can help
– Crop rotation-planting different crops at different
seasons or in different years (erosion and nutrient
loss)
– Altering shape (e.g. planting fields across, instead
of down and slope; reduce water runoff and
erosion.
Freshwater Resources
• Goods and services-drinking water, industry,
transportation, energy and waste disposal.
• Fresh water is renewable resource; some is not
– Ogallala Aquifer- spans 8 states (South Dakota to
Texas); more than a million years to collect; not
replenished by rainfall; expected to run dry in 20-40
years.
• 3% Earth’s water is fresh water- most locked in
ice at poles
Water Pollution
• Pollutant-harmful material that can enter
biosphere.
• Point source- pollution enter water supply from
single source (e.g. factory or oil spill)
• Nonpoint source- pollutant enters from many
smaller sources (e.g. grease and oil washed off
streets; chemicals released by factories and
autos)
• Primary sources-industrial and agriculture
chemicals; residential sewage; and nonpoint
sources
Industrial and Agricultural Chemicals
Industrial Chemicals
• PCBs-Chemical used in
industry until 1970s; largescale contamination events;
banned.
• Can be difficult, if not
impossible to eliminate
• Others-Cadmium, lead,
mercury and zinc
Agricultural Chemicals
• Pesticides and insecticides
• Runoff-enter water supply
• DDT-pesticide; dangerous,
controls against pest and
disease carrying
mosquitoes; threatened
fish-eating birds-females
laid fragile eggs; lowered
numbers
• Biomagnification
Biological Magnification
Pollutant concentrations
increase as they move up
the trophic levels.
DDT (dichlorodiphenyltrichloroethane)
Residential Sewage
• Household waste-becomes sewage
• Not poisonous-contains lots of nitrogen and
phosphorus
– Reasonable amounts-process and absorbed healthy
ecosystem
– Large amounts-blooms of algae and bacteria rob
water of oxygen.
– Dead zones-oxygen poor areas- fresh or salt water
• Sewage carry microorganism that can spread
disease.
Water Quality and Sustainability
• Protect natural systems involved in water
cycle.
• Watershed-land whose groundwater, streams,
and rivers drain into same place (lake or river)
• Sewage treatment can lower bacteria and
prevent dead zones
• Integrated Pest Management (IPM) instead of
pesticides-biological control
Water Quality and Sustainability
• Use of less-poisonous sprays
• Crop rotation
• Water conservation
– drip irrigation
Atmospheric
Resources
Common resource
whose quality has a
direct effect on health
*Provides Oxygen we
breathe
Ozone
• Form of oxygen-O3
• Natural; Upper
atmosphere
• Absorbs harmful UV
radiation from sunlight;
protecting skin from
cancer
Atmospheric Services
• Greenhouse Gases(CO2, Methane and
water vapor) regulate
global temperatures
– W/out Earth would be
30°C cooler
• Never “Used Up”
• Human activities can
have lasting impact
Air Pollution
• Air quality reduced-respiratory illnesses are
made worse and tend to increase.
• Globally-climate patterns may be impacted
Cause of Air Pollution
• Industrial processes
• Burning fossil fuels
Forms of Air Pollution
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Smog
Acid Rain
Greenhouse Gases
Particulates
Smog
• Gray-brown haze formed by chemical
reactions among pollutants released into the
air by industrial processes and automobile
exhaust.
Smog
• Products
– Ozone-High in atmosphere protective; ground
level, threatens health, especially those with
respiratory conditions.
• 2008 summer Olympics in Beijing
Acid Rain
• Rain containing nitric and sulfuric acids
• Cause-burning fossil fuel releases nitrogen and
sulfur compounds; combine with water vapors
and from acids.
• Effects
– kills plants
• Damages leaves
• Changes chemistry of the soil and surface water
– Dissolve and release mercury and other toxic
elements from soil (enter other parts of
biosphere)
Greenhouse Gases
• Burning fossil fuels and forest-release carbon
into atmosphere as CO2
• Agriculture-raising cattle to farming rice
releases methane and other green house
gasses.
• Contribute to global warming and climate
change.
Particulates
• Visible, microscopic particles from certain
industrial processes and certain diesel
engines.
– Ash, dust, soot, smoke aerosols
• Enter nose and mouth-to lungs and cause
serious health problems.
Air Quality and Sustainability
• Difficult to improve
– Doesn’t stay in one place
– Doesn’t “belong” to anyone
• Improvements
– Automobile emissions standards
– Clean-air regulations
– Phasing out of lead gas; now banned in US
Complete: Analyzing Data, page 164.
Biodiversity
Total of all the genetically based variation in all
organisms in the biosphere
• Variety of organisms
Types of Biodiversity
• Ecosystem Diversity-Variety of habitats,
communities and ecological processes in the
biosphere.
• Species Diversity- The number of different species
in the biosphere or in a particular area.
– 1.8 species identified and named
– 30 million more to be discovered
• Genetic Diversity-Sum total of all different forms
of genetic information carried by a particular
species, or all organisms on Earth.
Valuing Biodiversity
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Greatest natural resources
Contributions to medicine and agriculture
Provision of ecosystem goods and services
Make our world a beautiful, interesting place
Biodiversity and Medicine
Willow bark
• Wild species are
original sources of
many medicines
– Painkillers-aspirin
– Antibiotics-penicillin
• Blue green mold
– Chemicals in wild treat
diseases like
depression and cancer
Foxglove-Digoxin
for heart disease
Biodiversity and Agriculture
• Wild plants may carry genes we can use for:
– Plant breeding
– Genetic engineering- transfer disease or pest
resistance or other useful traits to plant crops.
Biodiversity and Ecosystem Services
• Number and variety in ecosystem can
influence stability, productivity and value to
humans.
• Keystone species can completely change an
ecosystem
• Healthy and diversity ecosystems play a role in
maintaining soil, water and air quality
Species Loss
• Scientist estimate 99% of species that have
lived are extinct
• Species loss is now approaching 1000 x’s the
“typical” rate.
• Human knowledge held in genes is lost
Species diversity/Genetic Diversity
• More genetically diverse, greater chances of
survival
• Human activity reduces genetic diversity;
species greater risk of extinction
• Ecosystems damages-organisms more at risk
Humans reduce biodiversity
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Altering habitats
Hunting
Introducing invasive species
Releasing pollution into food webs
Contribute to climate change
Altered Habitats
• Agriculture and urban development-loss of
habitats; some species become extinct
• Habitat fragmentation-development splits
ecosystems into pieces leaving “islands”
– Smaller island, fewer species
• More vulnerable- Open to attack or damage
Hunting and Demand for Wildlife
Products
• Hunting can lead to extinction
– Carolina parakeet
– Passenger pigeon
• Today endangered species protected; but not in
Africa, South American and Southeast Asia
• Hunting purposes
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Birds hunted for meat
Hides and skins for commercial value
Body parts of medicinal properties
Pets
• Habitat fragmentation leaves less hiding spaces
for prey
CITES
• Convention on international Trade in
Endangered Species
• Bans international trade in products from a list
of endangered species.
Introduced/Invasive Species
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Threaten biodiversity
Change ecosystems
Drive native species close to extinction
Economical loss
– E.g. Leafy spurge; infest millions of hectares across
Northern Great Plans; displaces grasses and other
plants; milky latex can sicken/kill cattle and
horses; ranchers and farmers losses exceeded
$120 million.
Pollution
• DDT-prevents birds from laying healthy eggs
• Peregrine Falcon #’s plummeted from use of
chemicals
• Acid Rain-stress on land and water organisms
• Increase CO2- dissolved in oceans making
more acidic, threatens environment
Climate Change
• Organisms have specific tolerance ranges to
abiotic factors; changes beyond tolerance can
be devastating; must be moved or face
extinction
• Estimates vary regarding effects of climate
change on biodiversity.
– 1.5 °C to 2.5 °C over late 20th century-30% species
are likely to face risk of extinction.
– Above 3.5°C risk is 40-70%
Conserving Biodiversity
• Protect individual species
• Preserve habitats and ecosystems
• Human neighbors of protected areas benefit
from conversation efforts.
Protecting Individual Species
• Association of Zoos and
Aquariums (AZA) oversees
species survival plans
(SSPs) that are designed to
protect threatened and
endangered species.
– Captive breeding programsbreed in controlled place
– Reintroduction programsback into habitat
• Currently 180 species are
covered by SSPs.
Preserving Habitats and Ecosystems
• Not just species, but the habitat
• Parks and Reservation-conservation efforts
• Marine Sanctuaries-coral reefs and marine
mammals
• Protect area large enough to protect
biodiversity
Ecological Hot Spots
• Place where significant numbers of species and
habitats are in immediate danger of extinction
• 1500 species of native vascular plants
• Lost at least 70% of original habitat
• 34 hot spots cover 2.3 of Earth’s land surface/ 50 % of
plant species & 42% of terrestrial vertebrates
Local Interest
• Individuals must change habits or way earn
living-incentive to those involved
– Tax credits- e.g. for solar panels; Energy Star;
hybrid cars
– Parks and preserves- attract tourist dollars
– Australia-farmers paid to plant trees; improved
water quality and improved cow’s health; shade in
the summer
Carbon Credits
• Incentives to Industry to cut fossil fuels
– Certain amount permitted to be burned
– Rest sold back at market value or traded to other
company
• Encourages
– Industries to pay for lower emissions machinery
– Adopt carbon saving practices
– Less financial burden
Ecological Footprint
Ecological Footprints describes
the total area of functioning
land and water ecosystems
needed both to provide and
the resources an individual or
population uses and to absorb
and make harmless the wastes
that an individual or
populations generate.
Ecological Footprints considerations
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Energy
Food you eat
Miles you travel
Electric use
Shelter
Waste and Sewage
Green house gases
Footprint limitations
• No way to calculate exact numbers
• No universal way to calculate footprint size
• Only a “snapshot” of situation at particular
time
Comparing Footprints
• Useful in making comparison among different
populations
• One data set-America has an ecological footprint
over 4 x larger thane the global average
• Per person use of resources in US
– 2x that in England
– 2x that in Japan
– 6x that in China
• Calculate Footprint for Country- footprint for typical
citizen and then multiply by size of population
Ecology in Action
• Future depends on:
– Ecological footprints
– Global population growth
– Technological development
• Ecological principles for sustainable future
– Recognizing the problem in environment
– Researching the problem to determine its cause
– Use scientific understanding to change behavior
http://www.youtube.com/watch?v=EjyrAHzthTo