Humans in the Biosphere and Sustainability

How have humans changed the Earth?

Hunting and Gathering Overhunting and poaching can put animal populations at risk of extinction. over-hunting led to a severe overkill of whale populations, and to endangerment of 5 whale species.

Agriculture Challenges for the future Although modern agriculture has increased world food supplies, it has also created ecological challenges. Use of farm chemicals (fertilizers and pesticides) can damage beneficial insects, contaminate water supplies, and accumulate in the environment. Farm machinery also burns many fossil fuels. Finding enough water for irrigation is another problem, because we are using water faster than the water cycle can replenish it.

INDUSTRIAL GROWTH and URBAN DEVELOPMENT The impact of humans on the biosphere was transformed by the Industrial Revolution during the 1800s.

Industrial Growth and urban Development Also, dense human communities produce lots of wastes that, if not disposed of properly, can affect air, water, and soil resources which impacts surrounding ecosystems. AND energy production requires burning fossil fuels which also impacts air quality and global climate.

Earth’s Resources Ecosystem goods and services are classified as either renewable or nonrenewable. Renewable resources- can be replaced or regenerated if they are consumed. Ex: wind, trees and forests, fisheries, air, land and fresh water If a resource is renewable does that mean the resource is unlimited? No, if it’s consumed faster than it can be replaced the resource will be used up.

Earth’s Resources In order to protect our renewable resources we must limit their consumption. Sustainable development- is a way to use these natural resources at a rate that does not deplete them. Ex: when forests are logged, new trees are planted in place of the harvested trees. This ensures the resources of the forest are not lost.

Earth’s Resources Nonrenewable resources- can not be replenished or replaced by the Earth’s natural processes within a reasonable amount of time. Ex: fossil fuels- oil ,coal, natural gas

How do human activities affect natural resources? Soil erosion Desertification Deforestation Overfishing Pollution Acid Rain Ozone Depletion

Soil Erosion Protecting our resources: Land/ soil is a resource that provides raw materials for industry, soil to grow crops in, and space for cities to develop on. Soil erosion- the wearing away of the surface soil by wind and water.

DESERTIFICATION Caused by a combination of farming, drought, and overdrawing groundwater Roughly 40 % of Earth’s land is considered at risk for desertification. This map shows vulnerable areas in North and South America.

DEFORESTATION Loss of trees/forest What happens if there are no trees or roots? (why is vegetation important?) SOIL EROSION, soil is exposed to heavy rain, especially in tropical areas!

Overfishing

Pollution Water Pollution Industrial and agricultural chemicals PCBS + DDT Biological magnification Residential sewage Nonpoint sources Air Pollution Smog Acid Rain Greenhouse gases Particulates

Industrial and Agricultural Chemicals One industrial pollutant is a class of man made organic chemicals called PCBs that were widely used in many industrial applications until the 1970s. After several large-scale contamination events, PCBs were banned. Other harmful industrial pollutants are heavy metals like cadmium, lead, mercury, and zinc.

Industrial and Agricultural Chemicals Large-scale monoculture has increased the use of pesticides and insecticides. These chemicals can enter the water supply in the form of runoff after heavy rains, or they can seep directly into groundwater. DDT (used mainly in the 1950s) effectively controls agricultural pests and disease-causing mosquitoes. But, when DDT gets into the water supply, biological magnification can occur. Biological magnification occurs if a pollutant, such as DDT, mercury, or a PCB, is picked up by an organism and is not broken down or eliminated from its body. Instead, the pollutant collects in body tissues.

Smog and Particulates Smog is a gray-brown haze formed by chemical reactions among pollutants released into the air by industrial processes and automobile exhaust. Particulates are microscopic particles of ash and dust released by certain industrial processes and certain kinds of diesel engines.

Acid Rain Affects: Plant life Aquatic environments Statues

Ozone Depletion The ozone absorbs harmful UV rays from sunlight before it reaches Earth’s surface. Burning fossil fuels and forests releases excess CO2, a greenhouse gas. Although some greenhouse gases are necessary (temp regulation), when excess greenhouse gases accumulate in the atmosphere, they contribute to global warming and climate change.

Biodiversity: the diversity of life Several types of biodiversity Ecosystem diversity (types of habitats, environments) Species diversity Genetic diversity Biodiversity has given us foods, medicines, and all kinds of products. Who knows what else it could provide for us?

Types of biodiversity Diversity of genes Chihuahuas, beagles, and rottweilers are all dogs—but they're not the same because their genes are different. Beagle Chihuahua Rottweilers

Types of biodiversity Diversity of species For example, monkeys, dragonflies, and meadow beauties are all different species. Golden Skimmer Meadow Beauty Saki Monkey

Types of Biodiversity Variety of ecosystems Prairies, Ponds, and tropical rain forests are all ecosystems. Each one is different, with its own set of species living in it. Paines Prairie Florida Sand hill Pond Hoh Rain Forest

What do we get from biodiversity? Medicine Herbal remedies, penicillin, etc. Agriculture Cross pollinating genetically advantaged plants Maintaining soil, clean water, and oxygen Variety of habitats, such as wetlands, help filter water Forests help recycle nutrients

Should we be concerned about biodiversity? What we know: The Earth is losing species at an alarming rate 3 species per hour are going extinct and 20,000 extinctions occur each year. When species of plants and animals go extinct, many other species are affected. Human activity plays a major role in these extinctions!

Threats to biodiversity Habitat destruction Number of species in area, including their genetic diversity drops Overhunting/fishing Pollution (DDT, Acid rain) Invasive species Global Climate Change Exploitation Overharvesting makes plants unable to regenerate fast enough.

Biodiversity Hot Spots Ecological hot spots: Habitats with species in immediate danger of extinction!

Ecological Footprint measures the extent to which humanity is using nature's resources faster than they can regenerate.

This world map shows each country in proportion to its ecological footprint.