Humans in the Biosphere Chapter 6 Mrs. Yanac. Limited Resources All organisms on Earth must share...
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Transcript of Humans in the Biosphere Chapter 6 Mrs. Yanac. Limited Resources All organisms on Earth must share...
Humans in the Biosphere
Chapter 6Mrs. 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 Hunting & Gatheringo Agricultureo Industryo 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 watero 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 resourceso Sustainable development would include
planting trees to replace those cut down
• Overfishing reduces fish populationso 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 fuelso Sustainable development would
include emission controls to reduce air pollution
• Sewage & discarded chemicals can pollute the water supplyo 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 radiationo CFC’s (found in aerosols) caused damage to the ozone o CFC’s have since been banned
• Global Warmingo 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