Human Activities Affect The Environment

1. Human Activities Affect The Environment • Humans Use Many Resources • Humans rely on the environment, and use renewable and nonrenewable resources • Pollution Endangers Biodiversity • Pollution= addition of harmful substances (chemicals, bacteria, dirt) to the environment (soil, air, water) • Biodiversity= number & variety of life forms within an ecosystem. (pollution decreases this) • Habitat Loss Endangers Biodiversity • If living space is limited or a food source is removed (due to pollution) then the number of species in a biological community will be reduced.

2. Humans use many Resources • RENEWABLE RESOURCE: resource that can be used over & over again (trees, sunlight energy, water). Can be replaced naturally or by humans in a short amount of time, but if overused or poorly managed, may run out (except for sunlight). • NONRENEWABLE RESOURCES: resources that cannot be replaced. May be replenished by natural processes, but not quickly enough for human purposes. Are often underground, but technology is making it easier to find & use up these resources. Coal, petroleum, & natural gas (all fossil fuels) are nonrenewable resources used for heating, industry, & transportation. Minerals like gold & copper are also nonrenewable.

4. Pollution: Air Quality • Air quality affects entire ecosystems; (1980 Mt. St. Helen eruption in West Coast, 3 days later ash landed in East Coast). • Fossil fuels release sulfur dioxide, nitrogen dioxide, & carbon monoxide into air, leading to acid rain. • Acid rain occurs when the above mix with water in air to form acid droplets of rain, snow, or mist. This has killed all the fish in some of New York’s lakes, and damages tree leaves and soil. This leads to habitat destruction and lower food source & less biodiversity.

5. Pollution: Water Quality • Chemicals or waste that drain off of farm fields, animal feedlots, & landfills, and oil spills, soil erosion & discharge of waste water all cause water pollution. (40 years ago this lead to Lake Erie having everything in it “die”) • This affects entire ecosystem; when fish & amphibians are exposed, entire food web is affected. If fish die off, birds may not have food, and either die or move to a new habitat. Biodiversity is then decreased. (Duwamish River in Washington has over 600 million gallons of untreated waste & storm water drain into it (bacteria & chemicals kill fish)

6. Pollution Across Systems • Pollution can spread among ecosystems by abiotic factors (wind with Mt. St. Helen ash, or acid rain). • Pollution can also move between air and water (chemical pollutants run off land into body of water, & may evaporate with water into air, moving into the atmosphere.

7. Habitat Loss • By humans removing natural resources, populations relying on those are less likely to survive. Removing large areas of land (due to land development) that is habitat to many species, takes away food, space, shelter & protection for them. • Sometimes humans move species into new habitats (on purpose or accidentally). This may drastically change the habitat. Over time, these Invasive Species may replace the native species by out competing them. • Purple loosestrife was brought to U.S. from Europe in 1800’s (as a garden plant & medicinal herb). 1 plant makes 2million seeds/yr. Carried by wind/water/animals /humans, the seeds sprout in wetlands to replace native plants that animals feed on. This causes animals to disappear with the native plants.

8. By protecting biodiversity, we can help ecosystems thrive & recover. This directly benefits humans (many medicines are based on natural compounds from plants that only grow in certain ecosystems).