1. Human Impact on Ecosystems

2. 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

3. 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

5. 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

6. 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

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

8. 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

9. 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

10. 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

11. 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

12. 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

13. CO2, Methane, other greenhouse gases
Earth

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

15. 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.

16. 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

17. Nitric acid
Sulfuric acid
SO2 NO NO

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

21. 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

22. 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.

23. 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

25. 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

26. 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

27. 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?