Humans in the
Biosphere
Chapter 6
Mrs. Yanac
Limited Resources
• All organisms on Earth must share the planet’s
resources and they are LIMITED.
• Humans are the main source of environmental
change:
o
o
o
o
Hunting & Gathering
Agriculture
Industry
Urban development
Hunting and Gathering
• Prehistoric hunters and gathers changed the
environment and even drove some species to
extinction.
Agriculture
• Farming increased the amount of food produced & allowed
cities to form
• People in cities produced wastes
• Advances in agriculture included use of pesticides &
monoculture (planting of same crop year after year) which
led to green revolution & an increase in world food supply
• Problems  Pollution from pesticides
Industry
• (-) Used more resources & produced more pollution
than ever before
• (+) Machines made life easier for humans
Urban Development
• Changes the landscape, displaces animals,
destroys habitat, causes pollution, etc
Renewable Resources
• Any resource that can be easily replaced or
replenished
Nonrenewable Resources
• Any resource that can NOT be easily replaced or
replenished (takes millions of years to replace)
Human Activities
• Threaten many resources & can affect the quality &
supply if renewable resources such as land, forests,
fisheries, air & fresh water
o Sustainable development is a way of using resources w/o depleting them
• Soil erosion occurs when water or wind remove
surface soil (removing nutrients & leaving land like a
desert  desertification)
o Sustainable development would include alternating crop planting &
contour planting
Human Activities
• Deforestation is the loss of forests which provide
oxygen, wood, & other resources
o Sustainable development would include
planting trees to replace those cut down
• Overfishing reduces fish populations
o Sustainable development would include
aquaculture (raising aquatic animals for food)
Human Activities
• Smog and acid rain are a result of air
pollution due to burning fossil fuels
o Sustainable development would
include emission controls to
reduce air pollution
• Sewage & discarded chemicals
can pollute the water supply
o Sustainable development would include
protecting wetlands & maintaining
regulations on wastewater treatment
Biodiversity
• Biodiversity is the sum of all kinds of organisms in the
biosphere
• ECOSYSTEM DIVERSITY – all habitats, communities,&
ecological processes in ecosystems
• SPECIES DIVERSITY – the # of different species in the
biosphere
• GENETIC DIVERSITY – the genetic info carried in all
living things on earth
Ecosystem Diversity
Species Diversity
Genetic Diversity
Threats to Biodiversity
• Humans alter habitats, hunt species to extinction,
introduce pollution into food webs & introduce
foreign species into new environments
• HABITAT FRAGMENTATION
• EXTINCTION
• BIOLOGICAL MAGNIFICATION
• INVASIVE SPECIES
Habitat Fragmentation
Extinction
• Several mass extinctions over geologic time (i.e.
Dinosaurs)
• Humans have driven many species to extinction
On the verge of extinction
• Many are listed as
o THREATENED – Population numbers are rather low
& they must be protected & monitored
o ENDANGERED – Population numbers are extremely low and they must be
protected,
Conservation
• Conservation is the
wise management of
natural resources
• Protecting entire
ecosystems as well as a
single species
• Protecting the
ecosystem ensures that
the natural habitat is
preserved & the
interactions of many
different species at the
same time.
The Future
• Effects on the Ozone Layer
o Ozone protects Earth from harmful radiation
o CFC’s (found in aerosols) caused damage to the ozone
o CFC’s have since been banned
• Global Warming
o Increased production of CO2 has thickened the “blanket” around the
earth resulting in the trapping of more heat, raising the average
temperature of the planet
o Runaway greenhouse effect (Global Warming) could result in coastal
flooding and drastic weather patterns