Human Impact on Ecosystems

Earth’s Human Population Continues to Grow Technology has helped to increase Earth’s carrying capacity. Earth’s human carrying capacity is unknown gas-powered farm equipment medical advancements clean water public assistance

The Big Problem: Overpopulation Over 6.6 billion people Many natural resources are nonrenewable Fossil fuels take millions of years to form More people means: 1) More forests removed 2) More resources consumed 3) More CO2 released

The growing human population = pressure on Earth’s natural resources MUST BE MANAGED EFFECTIVELY!!! Nonrenewable resources are used faster than they can form or be replenished: Coal Oil Natural Gas Renewable resources cannot be used up or can replenish themselves over time : Wind Solar Water

An ecological footprint is the amount of land needed to support a person. The land must produce and maintain enough food and water shelter energy Waste Several factors effect size: Amount/efficiency of resource used Amount/toxicity of waste produced

Caused by human activity? What are some Environmental issues Caused by human activity?

Ozone Layer Depletion Ozone Function: Block UV radiation from sun Problems: CFCs thinning the ozone layer More UV radiation reaches the surface Effects: Crop damage, skin cancers, Eye damage Solution: Reduce CFCs, regrow trees UV UV Ozone layer Ozone layer CFCs

The Smog and Ground-Level Ozone Reason: Burning of fossil fuels & industry Problems: Respiratory illness Ozone gas is poisonous Causes: Particulates rise into air and react with sunlight to make air pollution Solutions: Reduce use of fossil fuels alternative energy sources Plant trees

The Greenhouse Effect G.H.E. is naturally good (it warms Earth) Problem: Excess heat trapped near the earth’s surface Fear: Climate patterns change, ice caps melt Main Cause: CO2 from burning of fossil fuels (coal, oil, natural gas) Solutions: Reduce use of fossil fuels, regrow trees, alternative energy sources

What’s a Greenhouse? A Greenhouse is designed to trap heat so you can grow plants year round, even in cooler environments. heat Some heat escapes the greenhouse, but enough is trapped to keep the inside warm heat heat heat

Earth Some heat escapes into space heat Some heat naturally trapped by Earth’s atmosphere The Natural Greenhouse Effect is good! heat heat Earth The Atmosphere

CO2, Methane, other greenhouse gases Earth

Earth Less heat escapes into space heat heat heat More heat trapped near Earth’s surface heat heat Excess CO2 in atmosphere Earth

The Greenhouse Effect is naturally GOOD! Mars: No Greenhouse Effect Earth: Balanced Greenhouse Effect Venus: The Extreme Greenhouse Effect Little heat is trapped by the thin CO2 atmosphere. High temperatures can be around 20⁰F. Heat is trapped by the thick CO2 atmosphere. Temperatures reach 750⁰F. Average global temperature is 57⁰F.

Acid Rain Defined: Precipitation with a below normal pH Cause: Fossil fuel pollution rises into the air & then falls as rain Effect: Waterways more acidic Kills plant and animal life Solutions: Reduce fossil fuel usage Add buffer (base) to waterways

Nitric acid Sulfuric acid SO2 NO NO

Water pollution Defined: pollution in water supplies Causes: Waste Medicines Agricultural Runoff fertilizers pesticides Problems: Species lost Ecosystems harmed Solutions: Manage waste

Water pollution affects ecosystems Indicator species: Give sign of ecosystem’s health Example: Amphibians Frogs are good indicator species because their skin is water permeable. Top predators Solution: Waste Management

Biomagnification = Accumulation of toxins in the food chain Pollutants that are fat soluble can move up the food chain. These pollutants stay in the body fat of an organism predators eat contaminated prey Pollution accumulates at each stage of the food chain Top consumers, including humans, are most affected.

Deforestation Defined: Clearing of forested areas Reasons: High demand for wood products Create farmland Problems: Species lost Excess CO2 released Solutions: Recycle Improved farming techniques

Introduced (& Invasive) Species Defined: Foreign organisms are introduced to a new habitat Invasive- harms native species Reason: Pet industry, “free ride” organisms, pest control Effects: Foreign species outcompete native species Food webs unbalanced Economic damage Solutions: Laws preventing foreign goods into new countries Introduce predators Zebra mussels Mice Kudzu vines

What is being done? The Environmental Protection Agency (EPA) Created in 1970 Works to protect species Clean Water Act Clean Air Act Endangered Species Act This recovered the bald eagle) Those listed are called “Umbrella Species” Entire habitats protected

Review CFCs are manmade chemical responsible for the destruction of _________________. Which gas is a main contributor to the greenhouse effect? Crop damage and cancers are caused by an excess amount of which type of energy? Name the big three fossil fuels. Which planet has excess temperatures because of a thick CO2 atmosphere? Desert-like land is created as a result of which problem? Where is ozone gas harmful to life? Where is ozone gas helpful to life? Food webs become unbalanced as a result of the introduction of which type of organisms? Even though there may be space for people, why do those who study the environment consider humans to be overpopulated?