Transcript Slide 1
Ecology week 3 Human Impact on the Environment Humans in the Biosphere Like all organisms, we humans participate in food webs and chemical cycles. Among human activities that affect the biosphere are hunting and gathering, agriculture, industry, and urban development. Humans in the Biosphere By the end of the last ice-age – about 11,000 years ago – humans began the practice of farming, or agriculture Monoculture, fertilizers, and the green revolution. Industrial growth and urban development Human society and its impact on the biosphere (Earth) were transformed by the industrial revolution (1800’s) Dense human communities produce waste that must be disposed of. Certain industrial processes pollute air water and soil. Renewable and Nonrenewable resources Environmental goods and services may be classified as either renewable or nonrenewable Renewable resources: can regenerate if they are alive or can be replenished by biological cycles if they are non-living (abiotic), but they are not necessarily unlimited. “ex: freshwater” Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water. Soil erosion? Desertification? Renewable and Nonrenewable resources Nonrenewable resources: are those that cannot be replenished by natural processes • Fossil fuel • Coal • Oil • Natural gas • Nuclear energy??? Renewable and Nonrenewable resources Deforestation Overfishing (aquaculture) Air resources (smog, pollutant, acid rain) Freshwater resources Effects of Acid Rain Biodiversity Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere Biodiversity is one of Earth’s greatest natural resources. Species of many kinds have provided us with foods, industrial products, and medicines – including painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs Rosy Periwinkle (used to treat certain cancers) Biodiversity Human activities can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments Demand for wildlife products??? Pollution DDT Biological magnification??? Chloroflorocarbons (CFC’s) & the ozone layer. • UV ~ skin cancer, phytoplankton? Ozone Layer (O3) Many scientists are concerned about the thinning of the OZONE layer. How Populations Grow Exponential growth • Bacteria • Humans Logistic growth • Carrying capacity Predator / Prey relationships Human population Human Population Issues The end