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 Hunting & Gathering o Agriculture o Industry o 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 CO 2 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