Human Impact

Like all organisms, humans rely on Earth’s life-support systems. We affect our environment when we obtain food, eliminate waste products, and build places to live.

Humans affect regional and global environments through agriculture, development, and industry in ways that have an impact on the quality of Earth’s natural resources including soil, water, and the atmosphere.

Effects of agriculture: Producing food for the 7 billion people on Earth impacts resources like fresh water and fertile soil. Monoculture: is the practice of clearing large areas of land to plant a single highly productive crop year after year. Ex: soybeans

Renewable vs Nonrenewable Ecosystem goods and services are classified as either renewable or nonrenewable. A renewable resource can be produced or replaced by a healthy ecosystem. Ex: white pine trees A nonrenewable resource cannot be replenished by natural processes in a reasonable amount of time. Ex: coal

Sustainable development: using resources in an environmentally conscious way.

Negative impacts on Soil Quality Desertification: lower land productivity cause by over-farming, overgrazing, seasonal drought, and climate change. ~40% of the Earth’s land is considered at risk for desertification. Deforestation: loss of forests

Negative impacts on Freshwater Pollutants: harmful material that enters the biosphere. Ex: factory spills Biomagnification: increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain/food web. Ex: DDT, mercury

Negative Impacts to Atmosphere Smog: a grey-brown haze formed by chemical reactions among pollutants (industrial process + automobile exhaust) Acid rain: rain containing nitric and sulfuric acids. Caused by burning fossil fuels Greenhouse gasses: gasses that trap heat into the Earth’s atmosphere

Biodiversity Biodiversity is the total of all the genetically based variation in all organisms in the biosphere 3 types: Ecosystem diversity: variety of habitats, communities, and ecological processes Species diversity: variety of species in a given area Genetic diversity: different forms of genetic info

Biodiversity’s benefits to society include contributions to medicine and agriculture, and the provision of ecosystem goods and services

Humans reduce biodiversity by altering habitats, hunting, introducing invasive species, releasing pollution into food webs, and contributing to climate change.

What can we do? Reduce our ecological footprint 1. recognize the problem 2. research that problem 3. use scientific understanding to change our behavior