Impacts of Humans on Ecosystems

1. Impacts of Humans on Ecosystems

2. 5 Human Impacts on the Environment: Crash Course Ecology #10 http://www.youtube.com/watch?v=5eTCZ9L834s

3. Simpson Diversity Index

4. Simpson Diversity Index in Action: • Australian Aborigines improve biodiversity by starting fires. • The Martu tribe set fires to areas to reduce the dominance of spinifex grass and encourage the growth of other species. • They call this the ‘fire-stick farming’ hypothesis. http://www.dailygalaxy.com/my_weblog/2010/05/aboriginal-green-ancient-hunting-and-burning-enhance-australias-desert-biodiversity.html

5. Simpson Diversity Index in Action Example: Work through this example based on these simplified data: Great article: http://www.dailygalaxy.com/my_weblog/2010/05/aboriginal-green-ancient-hunting-and-burning-enhance-australias-desert-biodiversity.html

6. Calculating D is easy on Excel: Just set up the table in an easy-to-manage way

7. Processed Data: What has happened to diversity 5 years after burning? From the results, deduce which species is spinifex. What type of succession is modeled here?

8. Analyzing data - Simpson’s Diversity Index is a measure of:

9. Simpson’s Diversity Index – Why is it useful? • Assess the health of a habitat or area over time.

10. Note: The equation used here is actually Simpson's reciprocal Index*. In other sources, you may find the calculation for D as: * This means 1/D.

11. Why conserve the rainforests? Palm oil boom threatens jungle Why conserve the rainforests? http://www.youtube.com/watch?v=YHki3EgGzdY

12. Why conserve the rainforests? The Prince of Wales speaks about the worlds rainforests http://www.youtube.com/watch?v=M2Cqo1Aksv4

13. Why conserve the rainforests? Reasons for conservation of any habitat are many, but we can look at the question in terms of four main area of concern. When discussing conservation and decision making in science, it is also essential to ask the question:

14. Complete this mind-map of reasons to conserve the rainforest:

15. Complete this mind-map of reasons to conserve the rainforest:

16. Inspirational Rainforest Conservation How we re-grew a rainforest by Willie Smits • How does the project work? • How have they considered all of the stakeholders in order to ensure success of the project? • How is it economically viable? • What is likely to have happened to Simpson’s Diversity Index of the area over time? • Could this idea be used elsewhere? http://www.ted.com/talks/willie_smits_restores_a_rainforest.html

17. Alien Species

19. Cane Toads: Introduced on purpose, Invasive by accident. http://www.youtube.com/watch?v=rI8IiLqIEV0

20. Cane Toads: Introduced on purpose, Invasive by accident. • Australians are encouraged to kill cane toads when they see them, by putting them in a bag in the freezer. • Under development are biological control mechanisms based on viruses and parasites specific to the cane toad. Great article: http://larvalsubjects.wordpress.com/2010/05/23/in-case-anyone-wondered/

21. Use the Global Invasive Species Database to build a factsheet on one invasive species: http://www.issg.org/database/welcome/ • Find out information about: • Binomial and common names and taxonomy • Native and introduced geographical ranges. • Introduction pathways or vectors • Local dispersal methods • Impacts • Management strategies • Images KUDZU http://www.youtube.com/watch?v=iLH1qLCvqSg

22. Impacts of invasive species: Find out more: http://www.issg.org/database/welcome/ http://www.actionbioscience.org/biodiversity/simberloff.html

23. Biological control of invasive species. • This is the use or introduction of one organisms to control another invasive species. • Example: • RHDV (rabbit hemoragihic disease virus) have been introduced to Australia in order to control the population of rabbits. • Problem: • Rabbits introduced & population exploded. Widespread damage to crops and interspecific competition with local species. Pet rabbits still illegal in Queensland , Australia

24. Biological control of invasive species. • This is the use or introduction of one organisms to control another invasive species. • Solution: • Introduce RHDV, a virus specific to rabbits. (tested under quarantine first, & then released into wiled populations. Adult rabbits contact spreads the virus, but does not affect any other species. • Effectiveness: • Very effective, though some evidence of RHDV resistance in rabbits is starting to become apparent. Pet rabbits still illegal in Queensland , Australia

25. Biomagnification: A process in which chemical substances become more concentrated at each trophic level.

26. Biomagnification: A process in which chemical substances become more concentrated at each trophic level. • As each individual eats contaminated food or filters contaminated water, it is building up these chemical substances. This is known as bioaccumulation. Bioaccumulation occurs within one trophic level. • When a large number of contaminated individuals are eaten, they pass on a high concentration of chemicals to the predator. This increase in concentration up the trophic levels is Biomagnification.

27. Biomagnification of DDT • Cause: DDT is a synthetic pesticide sprayed on crops and can be used against malaria mosquitos. • It is washed into waterways in low concentrations, where it is biomagnified up the food chain. • It is highly toxic at high concentrations. • Consequences: • Stored in fats & accumulates quickly. • Very high concentrations in large fish & seabirds. • Responsible for reduced reproductive function & shell thinning in birds of prey • In humans it has been linked to cancers, fertility and developmental problems. http://web.bryant.edu/~dlm1/sc372/readings/toxicology/toxicology.htm

28. Ozone (O3) in the stratosphere absorbs UV radiation. • High concentration of ozone in this layer absorbs over 93% of al UV radiation which reaches Earth. • This layer can be depleted by chemical gasses including CFC’s (chlorofluorocarbons). These gases collect over polar regions & the cold temperatures allow for the depletion of the ozone layer by slitting CFC molecules, using UV. • The result is more harmful UV radiation reaching the Earth's surface, where it can cause damage to living things and contribute to global warming.

29. Ozone (O3) in the stratosphere absorbs UV radiation. NASA Explanation Ozone layer shielding the planet: http://www.youtube.com/watch?v=qUfVMogIdr8 http://svs.gsfc.nasa.gov/vis/a000000/a000800/a000834/index.html

30. CFC’s deplete the ozone layer. http://www.bom.gov.au/lam/Students_Teachers/ozanim/ozoanim.shtml Chlorine goes on to split more ozone molecules. It can split up to 100,000 molecules. At that rate, natural ozone production cannot compensate.

31. Elevated levels of UV are harmful to living organisms and biological productivity.

32. Check for skin cancer. http://www.beltina.org/health-dictionary/skin-cancer-types-symptoms-treatment.html Stay safe in the sun! Check the UV alerts in the area.