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 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 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