Topic 5: Ecology and Ecosystems

Biology 2 /SL Review Book Topic 5.2: The Greenhouse Effect Name ______

Review Book Topic 5: Ecology and ecosystems

Key facts Topic 5.2 The Greenhouse Effect 1. The carbon cycle is a major factor in the greenhouse effect. 2. The carbon cycle represents the interaction of living organisms and the biosphere through the processes of photosynthesis, cell respiration, fossilization and combustion. 29. Photosynthesis allows the fixation of carbon dioxide from the atmosphere. Combustion results in the release of and accumulation of more carbon dioxide in the atmosphere. Respiration results in the release of carbon dioxide and accumulation in the atmosphere. 3. Decomposers, saprotrophs and detritivores, result in release of carbon dioxide into the atmosphere, and therefore, the recycling of carbon. 4. Data presently being collected in our atmosphere is showing an increase in atmospheric carbon dioxide levels. This increase is thought to be adding to the greenhouse effect we are presently witnessing on our planet. 5. Antarctic ice shows a steady atmospheric level of carbon dioxide for two thousand years until 1880. From 1880 onwards the level of carbon dioxide has been steadily increasing. This finding is confirmed by readings from Mauna Loa, Hawaii. Both areas confirm an increase of carbon dioxide in the atmosphere of nearly 100 ppm. 6. Besides carbon dioxide there are other atmospheric gases contributed to the greenhouse effect. These gases include methane, oxides of nitrogen, and sulfur dioxide. 7. Greenhouse gases in the atmosphere trap some of the long-wave radiation of the sun, causing the Earth to be warmer than if the radiation escaped. This long-wave radiation comes from the short wavelengths of the sun’s rays that can pass easily through the atmosphere. The trapping of the long- wave radiation is thought to be a major cause of the global warming we are recording at present. 8. Even though there is no direct proof that the rise in carbon dioxide is causing global warming, there is reason to practice the “precautionary principle” concerning this gas. This principle holds that, if the effects of a human-induced change would be very large, perhaps catastrophic, those responsible for the change must prove that it will not do harm before proceeding. 9. This principle when applied to global warming says that the consequences of global warming are so severe and devastating that preventive measures are justified even it is far from certain that rapid global warming will result from current human activities. 10. The effects of global warming on the Arctic ecosystems include increased rates of decomposition of detritus previously trapped in permafrost, expansion of the range of habitats available to temperate species, loss of ice habitat, changes in distribution of prey species affecting trophic levels, and increased success of pest species, including pathogens. 11. These changes in the Arctic ecosystems would affect the whole world because of rising oceans, increased carbon dioxide release into the atmosphere, altered food chains and webs in the Arctic and associated areas, increased world pathogens, and extreme weather events. Biology 2 /SL Review Book Topic 5.2: The Greenhouse Effect Name ______

Draw assessment statements for this topic. 1. Draw and label a diagram of the carbon cycle to show the processes involved. Be certain to include photosynthesis, cell respiration, fossilization, combustion and decomposition.

Complete the following. 28. List three sources of carbon dioxide in our atmosphere.

29. What major biological process allows a decrease in atmospheric carbon dioxide levels? ______

30. The Gaia hypothesis views the biosphere on Earth as a single living organism because there appears to be a significant level of self-regulation. How does the carbon cycle contribute to this self-regulation?

31. Present some reasons for the increase in carbon dioxide levels in the Earth’s atmosphere since the 1800s.

32. Besides carbon dioxide, what are some other gases that may be contributing to the greenhouse effect? Biology 2 /SL Review Book Topic 5.2: The Greenhouse Effect Name ______

33. Explain why carbon dioxide levels seem to increase in areas during the winter but decrease in those same areas during the summer.

34. What wavelengths of light pass through the Earth’s atmosphere relatively easily? ______Which wavelengths of light do not so easily pass through the atmosphere? ______

35. How does the Earth’s atmosphere compare to a greenhouse?

36. Why is the Earth’s atmosphere warmer than outer space?

37. Discuss ways greenhouse gases could be decreased to possibly slow global warming.

38. Use the precautionary principle to discuss what actions we should take concerning global warming.

39. Give an example of the precautionary principle being used in the field of medicine.

40. What impact is global warming having on Arctic ecosystems?

41. How might this impact affect ecosystems throughout the world?