Human Impact on the Biosphere

As the human population grows, the demand for Earth’s resources increases.

Earth’s human population continues to grow. Earth’s human carrying capacity is unknown.

Technology has helped to increase Earth’s carrying capacity.

The growing human population exerts pressure on Earth’s natural resources. Nonrenewable resources are used faster than they form. –Ex: coal and oil Overuse of nonrenewable resources may lead to a crisis.

Renewable resources cannot be used up or can replenish themselves over time.

Effective management of Earth’s resources will help meet the needs of the future. Earth’s resources must be used responsibly. Careless use of resources makes them unavailable to future generations. Easter Island is an example of irresponsible resource use. travelchann el.com/sho ws/mysterie s-at-the- museum/vid eo/easter- island- mystery

An ecological footprint is the amount of land needed to support a person.

Several factors affect the size of the ecological footprint.

POLLUTION

Fossil fuel emissions affect the biosphere.

Pollutants accumulate in the air. Pollution is an undesirable factor added to the air, water, or soil. Smog is one type of air pollution. –sunlight interacts with pollutants in the air –pollutants produced by fossil fuel emissions –made of particulates and ground-level ozone

Smog can be harmful to human health.

Air pollution is changing Earth’s biosphere. The levels of atmospheric carbon dioxide rise and fall over time. High levels of carbon dioxide are typical of Earth’s warmer periods.

Global Warming

The greenhouse effect slows the release of energy from Earth’s atmosphere. methane ( CH 4 ) water (H 2 O ) carbon dioxide (CO 2 )

Global warming refers to the trend of increasing global temperatures. North Pole

Pollution of Earth’s freshwater supply threatens habitat and health.

Water pollution affects ecosystems. Pollution can put entire freshwater ecosystems at risk.

Indicator species provide a sign of an ecosystem’s health.

Biomagnification causes accumulation of toxins in the food chain. Pollutants can move up the food chain. –predators eat contaminated prey –pollution accumulates at each stage of the food chain –Top consumers, including humans, are most affected.

THREATS TO BIODIVERSITY

Biodiversity Biodiversity is a measure of the diversity of living things on the Earth. The biodiversity of our planet is decreasing as species go extinct due to loss of habitat, pollution, and climate change. As species go extinct, they affect their entire ecosystem and can cause a ripple effect. – This can make the ecosystem unstable and less able to cope with future changes.

Loss of Habitat As the human population increases, habitats are lost for many different species. Reasons for habitat loss – Living space – Growing food (farm land and cattle grazing) – Energy production (coal/oil mining &refinement, dams, windmills, fracking plants, etc.) – Other resources (mining, deforestation)

Loss of Habitat Habitat Fragmentation- When a barrier forms that prevents an organism from accessing its entire home range. – Example: Roadways In an attempt to solve this problem, some states are building underpasses and overpasses for wildlife to use so they can avoid busy roadways.

Introduction of New Species An introduced species (aka invasive species) is any organism that was brought to an ecosystem as the result of human action. Introduced species can disrupt an ecosystem. Native species have evolved together and therefore can coexist in their habitat. Introduced species have not evolved with the other organisms in the ecosystem and therefore can cause ecological damage.

Introduction of New Species If an environment has a niche that the introduced species can exploit or if they are better competitors in a particular niche, native species may be pushed out. Introduced species are also successful if there is a lack of predators to keep the population stable.

Affects on Populations and Carrying Capacity Humans and nonhuman disturbances can affect populations of organisms. If the disturbance affects the carrying capacity of the area, the population will be effected long term. If the disturbance does not affect carrying capacity of the area, the effects will be short term.

Examples Draw a graph for each of the following examples showing how you think the population will be affected – Deer population- An area is heavily hunted for a season – Aspen tree population- An invasive plant is introduced – Mosquitoe population- An area is sprayed with pesticide – Moose population- A highway is built through their habitat – Parrot population- Forests are clear cut to make room for farm land – Squirrel population- A fire burns through an area – Salmon population- A dam is built in a river connecting the ocean and their breeding beds. – Lizard population- a new predator is introduced

TOP ENVIRONMENTAL CONCERNS FOR ARIZONA

Climate Change Climate change has already started affecting Arizona’s ecosystems. Average temperatures have risen 2 degrees F in the last decade and this change is estimated to continue. Urbanization of large areas also increases the temperatures (concrete retains heat energy) – Raises night-time temperatures by as much as 10 degrees compared to adjoining natural areas

Water Overuse of rivers (such as the Colorado River) has caused these rivers to dry up and not be available for ecosystems farther down stream. Additionally, the increasing temperatures have decreased the precipitation and increased evaporation causing less water to be available.

Air Quality Major causes of Air Pollution in Arizona Car exhaust (and other fossil fuel pollutants) are major problems in the Phoenix area. – The Phoenix valley is a large city, highly dependent on cars for people to get around (no good public transportation). Fires add smoke the air. Dust particles forms haze. Ozone and smog concentrations rise with higher air temperatures, high amounts of sunlight, and growing energy use.

CONSERVATION AND SUSTAINABILITY

Sustainable Development To ensure Earth can continue to support, or sustain, a growing human population, it is important to secure the future of the Earth’s ecosystems. Sustainable development is a practice in which natural resources are used and managed in a way that meets current needs without hurting future generations.

Sustainable Development There are a wide range of resource management methods that can be implemented to protect the environment and preserve resources for future generations. – Example: Selective cutting rather than clear cutting trees – Example: Fishing harvest reductions and rotations of fish species

Protecting Natural Resources As we become more aware of the problems facing our planet, we have created laws and policies to help protect our important resources. The Environmental Protection Agency (created in 1970) – Clean Air Act – Clean Water Act – Endangered Species Act Setting aside areas as public land is another way that governments can protect ecosystems – National parks

Sustainability We, as humans have the ability and technology to change the extent of our impact on the biosphere. – We can control how fast our population grows – We can develop technology to produce more food and less waste – We can change our practices and take action to protect and maintain ecosystems.