Ecology week 3 Human Impact on the Environment

Humans in the Biosphere Like all organisms, we humans participate in food webs and chemical cycles. 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. Among human activities that affect the biosphere are hunting and gathering, agriculture, industry, and urban development.

By the end of the last ice-age – about 11,000 years ago – humans began the practice of farming, or agriculture 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. Monoculture, fertilizers, and the green revolution. Humans in the Biosphere

Industrial growth and urban development Human society and its impact on the biosphere (Earth) were transformed by the industrial revolution (1800’s) 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. Dense human communities produce waste that must be disposed of. Certain industrial processes pollute air water and soil. Certain industrial processes pollute air water and soil.

Renewable and Nonrenewable resources Environmental goods and services may be classified as either renewable or nonrenewable 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. 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” “ex: freshwater” Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water. Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water. Soil erosion? Soil erosion? Desertification? Desertification?

Nonrenewable resources: are those that cannot be replenished by natural processes Nonrenewable resources: are those that cannot be replenished by natural processes Fossil fuelFossil fuel CoalCoal OilOil Natural gasNatural gas Nuclear energy???Nuclear energy??? Renewable and Nonrenewable resources

Deforestation Deforestation Overfishing (aquaculture) Overfishing (aquaculture) Air resources (smog, pollutant, acid rain) Air resources (smog, pollutant, acid rain) Freshwater resources Freshwater resources Renewable and Nonrenewable resources

Effects of Acid Rain

Biodiversity Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere 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 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 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??? Demand for wildlife products???

Pollution DDT DDT Biological magnification??? Biological magnification??? Chloroflorocarbons (CFC’s) & the ozone layer. Chloroflorocarbons (CFC’s) & the ozone layer. UV ~ skin cancer, phytoplankton?UV ~ skin cancer, phytoplankton?

Ozone Layer (O 3 ) Many scientists are concerned about the thinning of the OZONE layer. Many scientists are concerned about the thinning of the OZONE layer.

How Populations Grow Exponential growth Exponential growth BacteriaBacteria HumansHumans Logistic growth Logistic growth Carrying capacityCarrying capacity Predator / Prey relationships Predator / Prey relationships Human population Human population

Human Population Issues

The end