CHAPTER 20 Human Impacts on the Environment

1. CHAPTER 20 Human Impacts on the Environment Outline: I. Introduced species II. Human impacts III. The biodiversity crisis IV. Conservation biology V. The goal of sustainable development

2. About 12% of all known bird species are endangered

3. One-third of all vertebrate species live on just 15% of Earth’s land

4. Purposefully introduced invasive species have cost the US economy $130 billion

5. Human impact

6. I. Introduced Species • Are species that humans intentionally or accidentally move from the species’ native (home) locations to new geographic regions. • Examples: • The European starling • Argentine ants • The zebra mussel What is the number of introduced species in the US? Can you name some species native to the US?

7. European starlings

8. Argentine ants ganging up on a NATIVE red ant

9. Zebra mussels

10. II. Human Impact on Ecosystems • Human population has markedly changed natural habitat systems. • A. Impacts on Chemical cycles • Carbon- increased burning of fossil fuels • Nitrogen & Phosphorus - fertilizers & sewage treatment facilities  • Water – irrigating crops & deforestation eutrophication

11. Carbon dioxide producers

12. Eutrophication causing algal bloom

13. Deforestation ...by burning

14. Human impacts of releasing toxins • The release of new toxic materials cannot be degraded by microorganisms • Toxins can accumulate in tissues of animals • Biological magnification • A process in which toxins become more concentrated in successive trophic levels of a food web

15. Biological magnification

16. Human Impact on the Atmosphere and Climate • Carbon Dioxide Emissions • Since industrial revolution CO2 has increased in atmosphere • The Greenhouse Effect • Retains solar heat in the atmosphere • Increased global temperatures have potentially disastrous consequences Burning fossil fuel Remember the film?

17. Increase atmospheric CO2, temp variation 17%!

18. Factors influencing greenhouse effect

19. How do changes in number of producers and consumers influence production and uptake of global CO2? How do different types of industry influence global CO2?

20. Depletion of Atmospheric Ozone • The ozone layer absorbs UV radiation • Thinning since 1975 due to CFC’s • Consequences- • Increased skin cancer, cataracts • Amphibian population declines

21. Thickness of ozone layer decreasing 1979 2000

22. III. The Biodiversity Crisis is serious! • Human activity is causing a decline in the Earth’s great variety of life • A. Biodiversity has three main components 1. the diversity of ecosystems 2. the variety of species that makeup communities 3. the genetic variation within each species

23. Tropical rain forest ...full of biodiversity!

24. B. The Loss of Species • The current mass extinction - worldwide • Caused by human activity • Broader & faster than past extinctions • 12% of known bird species • 24% of known mammal species are threatened with extinction • Biologist Edward O. Wilson has compiled the Hundred Heartbeat Club • Species with fewer than 100 individuals

25. < 100 ww! Philippine eagle Chinese river dolphin Javan rhinoceros

26. C. Three Main Causes of the Biodiversity Crisis • 1. Habitat Destruction • Is the single greatest threat to biodiversity • 2. Introduced Species • Ranks second behind habitat loss. Can cause rapid extinctions • 3. Overexploitation of wildlife Human alteration of habitat

27. Habitat destruction

28. Introduced species Lake Victoria, East Africa

29. Overexploitation Do you like bluefin tuna? Do you eat sushi?

30. D. Why Biodiversity Matters • Humans rely on biodiversity for • Food, clothing, shelter, oxygen, soil fertility, medicinal substances • Endemic species • Are those found nowhere else • The loss of diversity • Limits the potential for new discoveries of food and medicine Drugs from plants!

31. IV. Conservation Biology A science that seeks to counter the loss of biodiversity • Biodiversity hot spots • Small areas with an exceptional concentration of species, including endemics

32. Terrestrial biodiversity hot spots Notice California ? Do you understand why its important to preserve biodiversity in CA?

33. Conservation at the Population & Species Levels • The U.S. Endangered Species Act (ESA) • Definition: endangered species • “…a species in danger of extinction throughout all or a significant portion of its range” • Definition: threatened species • “…a species likely to become endangered in the foreseeable future”

34. Habitat & Population Fragmentation • Fragmentation can results in • A decrease in the overall size of populations • A reduction in gene flow among subpopulations • Harmful side effect of human habitation Consequence: severe habitat degradation

35. Mt. Hood National Forest ? Northern spotted owl

36. What Makes a Good Habitat? • Identifying the specific combination of habitat factors that is critical for a species is fundamental to conservation biology • Example: Polar Bears

37. Conserving Species amid Conflicting Demands • Competing demands for habitat • Edges and corridors between ecosystems • Promote dispersal & help sustain populations • Especially important to species that migrate between different habitats seasonally • Jobs in • Timber • Mining • Loss of livestock • Camping safety • The owl • Wolf • Grizzly bear • Bull trout VS

38. Natural edges between ecosystems

39. Edges created by human activities Heavily logged rain forest in Malaysia

40. An artificial corridor

41. V. The Goal of Sustainable Development • Sustainable development • Balances human needs with the health of the biosphere • The goal of sustainable development • Is the long-term prosperity of human societies and the ecosystems that support them

42. Some Ways You Can Promote Sustainability Reduce consumption • Buy less • Avoid excess packaging • Avoid products make from non-renewable resources • Fix things rather than discarding them Be more energy efficient • Bike, walk, take public transportation, drive less • Share rides • Purchase efficient appliances and vehicles

43. Promote recycling • Recycle at home and at work • Purchase products made from recycled materials Promote research and education • Talk about environmental issues with friends, family • Sponsor environmental initiatives on your campus • Serve as a role model through your actions …more on Table 20.1

44. Biophilia and an Environmental Ethic • Edward O. Wilson • Biophilia  the human desire to affiliate with other life in its many forms, is innate Do you have pets? houseplants?

45. …Respect Earth’s biodiversity Near Walden pond

46. …the look of ‘biophilia’ on his face passion for nature

48. 1. Severe population _________ is one of the most severe consequences of habitat degradation. 2. Carbon dioxide traps heat and warms the atmosphere, a process called the _________ effect. 3. It is hard to protect species such as the monarch butterfly, sea turtles, and many songbirds, because they _________. 5. Fertilizer runoff can result in the _________ of lakes. 6. The goal of _________ development is to ensure that each generation inherits adequate resources and a stable environment. 7. Most biodiversity hot spots are in the _________.

49. 8. Biological _________ of pesticides harms animals at the top of the food chain. 10. Human alteration of _________ is the greatest threat to biodiversity. 14. The Earth is facing a serious _________ crisis. 18. The _________ is a law that protects endangered and threatened species. 20. In the US, 25% of prescriptions contain substances derived from _________. 22. Burning of _________ fuels produces carbon dioxide that may contribute to global warming.

50. Reading Assignment for: Next week, 12/4/07 & 12/6/07 Chapter 17 The Evolution of Animals