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Human Impact on the Environment

Human Impact on the Environment

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Human Impact on the Environment

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  1. Human Impact on the Environment

  2. Human Age Distribution Developed countries Less-developed countries

  3. Human Population Growth

  4. Population Growth and Environmental Impact Human population growth pressures physical environment, need for space and raw materials is going up People in developed nations have a greater demand for raw materials and generally more wasteful than underdeveloped countries

  5. Population growth leads to • Industrialization • Burning fossil fuels • Non-renewable resources • Pollution • Increased CO2 levels

  6. Human impacts on the environment Global warming • Use of machinery by humans seems to be increasing atmospheric CO2 levels. Carbon dioxide prevents heat energy from escaping, causes slight world wide temperature increases Rising water temperatures causes coral bleaching

  7. Acid Rain • Burning of fossil fuels releases sulphates and nitrates into air • Sulphates and nitrates mix with water vapor in air and form sulphuric acid and nitric acid

  8. Acidification of lakes • Lakes and ponds can become so acidified that no life can live in them!

  9. Deforestation • Population growth leads to the loss of natural habitats • Cut down trees to build new homes • Loss of biodiversity • Loss of oxygen producers and CO2 eliminators

  10. Human impacts on the environment Deforestation • Caused by demand for wood products, need for space, farmland, housing, roads • Deforestation causes habitat fragmentation • Animals and plants are forced into confined areas

  11. Herbicides and Pesticides • We spray pesticides and herbicides with out knowing the consequences • DDT

  12. DDT • Claimed to be a miracle • No effect on humans • Can build up in the environment • Biological magnification

  13. Bioaccumulation • Accumulated to such levels in top predators that it started having lethal effects. • Endangered many species of birds, Including our Bald Eagles.

  14. Human impacts on the environment Invasive species • Typically introduced by people accidentally or intentionally • Can cause problems if no natural enemies are present • Islands and other confined ecosystems are at risk Cane toad was introduced to Australia to control cane beetles, pest insects that destroy sugar cane crops Toads did not control cane beetles, instead they took over and cane toads are unusually hardy

  15. Ozone depletion • In the ’80’s it became apparent that the ozone layer was disappearing • It was confirmed that is was directly caused by human activity

  16. Human impacts on the environment Ozone depletion • Caused by aerosol chemicals called chloroflurocarbons (CFCs) commonly used as coolants • Escape into atmosphere, reacts with ozone (O3, a protective atmospheric layer) • UV rays penetrate atmosphere and cause harm to many organisms

  17. CFC’s • Carbon-Flouro-Carbons in aerosols were leaking into the atmosphere and eating away the ozone • Freon is also a CFC

  18. Pollution • Water Pollution • Oil Spills • Gasoline spills • Gets into drinking water

  19. Importance of the environment Biodiversity = Cast of characters • Many different types of organisms • Organisms depend upon one another • Photoautotrophs plants, algae • Chemoheterotrophsd herbivores, carnivores

  20. Importance of the environment Food chain • Photoautotrophs obtain energy from sunlight • Energy passed on to primary consumers and then secondary consumers • Each level up receives a lesser amount of energy

  21. Importance of the environment Natural resources • Non-renewable and renewable resources • Non-renewable includes fossil fuels (petroleum, coal) • Renewable includes animals, plants, water, wind, etc. • But, even renewable resources can run outand there are trade offs or consequences to using certain resources

  22. Importance of the environment Natural resources • Agriculture has many purposes such as food, textiles, wood, paper

  23. Importance of the environment Natural resources • Advances in biochemistry have allowed us to make synthetic chemicals such as antibiotics, glues, or use organisms to restore environments (bioremediation) Bacteria can be genetically altered to consume crude oil and other contaminants

  24. Importance of the environment Natural resources • Renewable energy sources include wind power, geothermal energy, ocean currents