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CHAPTER 6 HUMANS IN THE BIOSPHERE. SECTION 1 A CHANGING LANDSCAPE. Key Concept Question:. What types of human activities can affect the biosphere?. What is carrying capacity? the largest number of individuals that an environment can support What do you think would be the
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Key Concept Question: • What types of human activities can affect the biosphere?
What is carrying capacity? • the largest number of individuals that an environment can support What do you think would be the consequences of exceeding Earth’s carrying capacity? • overcrowding, shortage of food and water, shortage of fuel, malnutrition, increased disease
Humans and the Environment • Humans now live in almost every kind of ecosystem on Earth. • As human population increases, the impact of humans on the environment increases. • Humans are a part of the environment and can affect the resilience of the environment. The more that the human population grows, the more resources from the environment we will need to survive.
Earth is an interconnected planet: we depend on the environment, and the environment is affected by our actions. • Learning about this connectedness helps us care for the environment and ensures that the environment will continue to support us and other species on Earth.
What types of human activities can affect the biosphere? • hunting and gathering • agriculture • industry • urban development
*According to a recent study, human activity uses as much energy as all of Earth’s other multicellular species*
Let’s think about how humans have changed throughout history.
MONOCULTURE • large fields were cleared, plowed, and plantedwith a single crop year-after-year. • needed irrigation • chemical fertilizers • pesticides needed • human and animal power replaced by machines
What are the advantages of using agricultural machines such as tractors and harvesting combines? • Vast acreages can be plowed, sown, and harvested in less time and with fewer people enabling farmers to produce large crops
What are the disadvantages? • initial cost, and cost of repairs and maintenance • increased energy resources are used • release of exhaust gas into the air • noise pollution
Results of the Industrial Revolution during 1800’s • reliance on fossil fuels • increased use of mineral resources • large-scale production of manufactured goods
Suburban sprawl • The spread of suburban communities across America
Problems • large amounts of waste that needs to be disposed of • consumes farmland • consumes natural habitats • places stress on native plants and animals
Key Concept Question: • What types of human activities can affect the biosphere? • hunting and gathering • agriculture • industry • urban development
Key Concept Questions: • How are environmental resources classified? • What effects do human activities have on natural resources
Resources • Earth’s resources are described as renewable or nonrenewable. • Renewable resources are natural resources that can be replaced at the same rate at which they are consumed. • A renewable resource’s supply is either so large or so constantly renewed that it will never be used up.
RENEWABLE RESOURCES • Trees • Water • Air
Nonrenewable resources are resources that form at a rate that is much slower than the rate at which they are consumed. • Most of our energy today comes from fossil fuels. • Fossilfuels are nonrenewable energy resources that formed from the remains of organisms that lived long ago.
Fossil fuels such as coal, oil, and natural gas, are nonrenewable resources because it takes millions of years for them to form. • We use fossil fuels at a rate that is faster than the rate at which they form. So, when these resources are gone, millions of years will pass before more have formed.
How can people be sure that renewable resources will be available for future generations?
SUSTAINABLE USE • a way of using natural resources at a rate that does not deplete them • use of biological pest control instead of pesticides • rotating animal grazing grounds • planting trees after others have been cut down
Sustainable development manages resources for present and future generations. • Sustainable development meets needs without hurting future generations. • resources meet current needs • resources will still be available for future use
The timber industry has started to adopt sustainable practices. • Global fisheries have adopted several sustainable practices. • rotation of catches • fishing gear review • harvest reduction • fishing bans
What effect do human activities have on natural resources? • Human activities affect the supply and the quality of renewable resources
Land Resources • space for cities and industry • supplies raw materials • soil for crops
Soil Damage • Fertile soil allows agriculture to supply the world with food. • Fertile soil forms from rock that is broken down by weathering. • Nutrients that make soil fertile come from the weathered rock as well as from bacteria, fungi and the remains of plants and animals. • The processes that form just a few centimeters of fertile soil can take thousands of years.
The greatest threat to soil is soil erosion. • Erosion is a process in which the materials of Earth’s surface are worn away by wind, gravity, or water.
DESERTIFICATION • In certain parts of the world with dry climates, a combination of farming, overgrazing, and drought has turned once productive areas into deserts
Ecosystem Disruption • Ecosystem disruptions can result in loss of biodiversity, food supplies, potential cures for diseases, and the balance of ecosystems that supports all life on Earth. • We cannot avoid disrupting ecosystems as we try to meet the needs of a growing human population. • We can learn about how our actions affect the environment so that we can create ways to conserve it.
Over the last 50 years, about half of the world’s tropical rain forests have been cut down or burned for timber, pastureland, or farmland. This process of clearing forests is called deforestation. • The problem with deforestation is that as the rain forests and other habitats disappear, so do their inhabitants. • Habitat destruction and damage cause more extinction and loss of biodiversity than any other human activities do.
How We Can Help • replant trees • new tree varieties are being created to grow faster
Ocean Resources • food Problem • over fishing stresses ecosystems How We Can Help • limits on numbers of fish caught
AQUACULTURE • Farming of aquatic ecosystems
Air Resources • Fossil fuel emissions affect the biosphere.
Pollutants accumulate in the air. • Pollution is any undesirable factor added to the air, water, or soil. • Smog is one type of air pollution. • sunlight interacts with pollutants in the air • pollutants produced by fossil fuel emissions • made of particulates and ground-level ozone • microscopic particles of ash and dust that can enter the nose, mouth, and lungs, causing health problems over a long term
Smog can be harmful to human health. • Acid rain is caused by fossil fuel emissions. • produced when pollutants in the watercycle cause rain pH to drop • can lower the pH of a lake or stream • can harm trees
How We Can Help • strict automobile emission standards • technology to reduce emissions from smokestacks of factories
Water Resources • drinking • washing • watering crops
Water pollution affects ecosystems. • Pollution can put entire freshwater ecosystems at risk.
Water Pollution • Water pollution can come from fertilizers and pesticides used in agriculture, livestock farms, industrial waste, oil runoff from roads, septic tanks, and unlined landfills. • Pollution enters groundwater when polluted surface water percolates down through the soil. • Landfills and leaking underground septic tanks are also major sources of groundwater pollution.
