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Human Impact on Ecosystems

Human Impact on Ecosystems. Refers to the variety of life in an area. Biodiversity. Why is Biodiversity important? It’s not just about the aesthetics…. Life depends on life… *biodiversity brings stability to an ecosystem

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Human Impact on Ecosystems

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  1. Human Impact on Ecosystems

  2. Refers to the variety of life in an area Biodiversity

  3. Why is Biodiversity important? It’s not just about the aesthetics… Life depends on life… *biodiversity brings stability to an ecosystem *living things create niches for other living things; more living things, more niches… *symbiotic relationships can be effectively established or maintained *effective food webs can be established or maintained when there are more orgs

  4. Importance of Biodiversity to humans? • Production of oxygen and carbon dioxide • Wider choice of Diet • Prevention of starvation • Cross-breeding can happen more easily, making stronger, hardier organisms • More Materials for clothes, furniture, buildings • More medicines

  5. Loss of Biodiversity – extinct vs. endangered vs. threatened • Extinct – no orgs of that species exist • Endangered -- population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters • Threatened -- any species which is likely to become endangered within the foreseeable future throughout all or a significant portion of its range

  6. Threats to Biodiversity: 1. Habitat loss/destruction (this one is the number one concern!) 2. Habitat fragmentation 3. Habitat degradation 4. Introduction of Exotics/Invasive Species

  7. Threats to Biodiversity • Habitat loss – destruction of area *deforestation *clear-cutting grasslands *draining wetlands

  8. Habitat degradation (damage to habitat by pollution) Pollution: any undesirable factor that is added to air, water or soil. *3 types of pollution: air, land, water

  9. Air pollution -greatest source of air pollution is the burning of fossil fuels *Smog: can create breathing problems -- asthma; irritates lining of mouth and nose *acid precipitation (acid rain); pH drops *damage to ozone layer – natural filter for uv radiation is being lost *Global warming due to greenhouse effect

  10. Global warming • http://www.youtube.com/watch?v=oJAbATJCugs • See page 490-492 in textbook….

  11. Water Pollution • Additions of solid or liquid waste that is not naturally occurring in a body of water Ex. Excess fertilizer and animal waste wash into streams, rivers, lakes, ponds, and oceans cause ALGAL BLOOMS

  12. Algal Bloom: freshwater river 9-23-1999 9-29-1999

  13. Red Tide – oceanic algal bloom

  14. Indicator species • Also knows as bioindicator • Species that provides a sign or indication of the quality of the ecosystem’s environmental conditions Ex. amphibians http://www.youtube.com/watch?v=u6gW-1m1reI

  15. Land Pollution • Trash, garbage, and litter *average American produces ~1.8 kg of solid waste daily • Pesticides: increase in concentration of a substance (toxin) from one link in a food chain to another – • causes BIOMAGNIFICATION in food web • Ex. DDT effects on eagles

  16. Page 495

  17. DDT and eagle eggs…

  18. Introduction of Exotic species or Invasive Species • “Exotic” meaning not native to an area • Problem is that there are NO NATURAL PREDATORS, so the new species grows unchecked and can get out of control • Ex. Kudzu, fire ants, zebra mussels

  19. Kudzu covers EVERYTHING – even other plants!

  20. Zebra mussels

  21. Fishzilla video clip • http://channel.nationalgeographic.com/channel/videos/fishzilla-snakehead-invasion/

  22. Conservation Biology • Studies methods and implements plans to protect biodiversity. • Effective plans are based on principles of ecology • HUMANS ARE HUGE PART OF THE PROBLEM, so education is a key part of conservation biology…

  23. Biologist, Writer, Ecologist Figure 50.3 Rachel Carson Silent Spring

  24. Legal protection of species • 1973 – U.S. Endangered Species Act put into effect

  25. Source: http://ecos.fws.gov/tess_public/StateListing.do?state=all = updated daily

  26. Preserving Habitats • Nature preserves 1872, first national park – Yellowstone • Sustainable use – strives to let people use the resources of wilderness areas in ways that will not damage the ecosystem Ex. Eskimos hunting seal and walrus in Alaska Global fisheries – page 503 *rotation of species to catch *fishing gear review *harvest reduction *fishing bans

  27. Habitat corridors – natural strips that allow the migration of organisms from one area to another

  28. Reintroduction Programs vs. Captivity • RIP -- Release orgs into an area where their species once lived • Captivity – org that is held by people; reintroduction of these orgs is VERY difficult, if not impossible

  29. Precautionary Principle • In situations where absolutes are not known but problems are suspected: Set the acceptable levels of the suspected substance conservatively low, and keep them there unless future studies show that they can be safely raised.

  30. Importance of recycling, reusing • CUT DOWN ON SOLID WASTE that will be left behind • Use biodegradable materials that will decay • Recycle materials that WON”T decay for other uses • BE AWARE!

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