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Humans in the
Biosphere
Chapter 6
A Changing Landscape
• Human activities
– Among human activities that affect the
biosphere are hunting and gathering,
agriculture, industry, and urban
development
– Human participate in food web and
chemical cycles
– Human change the local and global
environments
A Changing Landscape
• Hunting and gathering
– people who obtain food by collecting and
hunting wild animals.
– Some scientist hypothesize that 12,000
years ago caused major extinction.
• Example – woolly mammoths, saber-tooth cats
A Changing Landscape
• Agricultural Revolution – When hunters
and gathers started collecting seeds to
plant and domesticating animals.
agriculture provides human society
with fundamental needs
dependable food supply
large quantity of food
Storage for excess food
A Changing Landscape
• Monoculture – large fields planted with one type of
crop
• Fertilizer – chemical or natural boost for plant growth
• Pesticide – chemical or natural controls for pest or
insects
• Green revolution – the use of genetic hybrids,
monoculture and chemical fertilizers the increased
world food supply
• Challenges for the future
– More insects
– More pesticides – kill good insects, produce runoff,
contaminate water supply
– Irrigation
A Changing Landscape
• Industrial revolution – the shift from animal muscle to
energy provided by water and fossil fuels which
brought about sophisticated machines.
– Pros – mass production of materials, more
advanced machines, more mobility, advance
medicine
– Cons – air pollution, soil pollution, water pollution,
waste disposal.
– Pollution – An undesired change in air, water or
soil that adversely affects the health, survival, or
activities of humans
Renewable and Nonrenewable
Resources
• Natural resources – any natural material
used by humans
– Renewable resource – sources that can be
replaced. Give some examples!
– Nonrenewable resourced – a resource that
is consumed at a faster rate than
replenished.
Renewable and Nonrenewable
Resources
• Sustainable development – a way of
using natural resources without
depleting and providing for human
needs without causing long term
environmental harm
• Humans affect quality and supply of all
resources
Renewable and Nonrenewable
Resources
• Land resources – provide space for human communities and raw
material humans need
– Food grow best in fertile soil made up of a mixture of sand,
clay, rock particles and humus
– Plowing of soil remove roots that hold soil together
– Soil erosion – wearing away of soil by wind or water
– Desertification – the process where over farming and dry
conditions turn a once productive area into a desert
• Ways to keep it from happening
– Leave stems and roots from previous crop on
farmland
– Sowing a fast growing cover - rye
Renewable and Nonrenewable
Resources
• Forest resources – important resource for products they provide
and the ecological functions they perform
• Wood is used for fuel and building material
• Forest can
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–
–
–
–
provide nutrients
Provide habitat
Limit soil erosion
Moderate climate
Protect fresh water supply
– Deforestation – loss of forest
• Species can be lost
• Severe erosion
• Change soil and microclimates
Renewable and Nonrenewable
Resources
• Fishery Resources
– Fishes and other animals that live in water are valuable source of
food
– Over fishing – harvesting fish faster than they can reproduce
• Declining of fish is an example of the tragedy of commons
– Over use of and area
– Fisheries help replenish this resource
– Sustainable Development – regulations that help the fish pollution to
recover.
• Guidelines can specify how many fish and what size of fish can be
caught in a given area
– Aquaculture – the raising of aquatic organisms for human
consumption
• Helps sustain populations
Renewable and Nonrenewable
Resources
• Air Resources – resources the air provides organisms
• Oxygen, carbon dioxide, nitrogen
– Condition of air affects people
– Smog – mixture of smoke and fog usually found in
highly populated regions
– Pollutant – harmful material that can enter the
biosphere through the land, air or water
– Acid rain – rain with high acidity. Caused by
burning of fossil fuels that release sulfuric and
nitric acid into the air.
Renewable and Nonrenewable
Resources
• Freshwater Resources
– Water is a renewable resource but
freshwater is limited
– Major priority must be given to protect
freshwater from pollution.
• Protecting wetlands
• Protect forest \protect swamps
• Prevent soil pollution
Biodiversity
• Biodiversity – the sum total of the genetically based
variety of all organisms in the biosphere
• Ecosystem diversity – the variety of habitats,
communities, and ecological processes in the living
world
• Genetic diversity – the total sum of all the genetic
information carried by all the organisms on earth
• Biodiversity is one of the earth’s greatest resources.
• Species of many kinds have provided us with
food, industrial products, and medicine.
Biodiversity
• Threats to biodiversity
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Hunting species to extinction
Introducing toxins
Introducing foreign species to new areas
Altering habitats
– Extinction – when a species disappears from all or part of it’s
range
– Endangered species – species population size declines to
almost extinction
– Habitat fragmentation – splitting of ecosystems into pieces
• Development of farms or communities
Biodiversity
• Pollution