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
1. 50K 2. timber wolf
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. The current mass extinction - worldwide
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
The owl
Wolf
Grizzly bear
Bull trout
Jobs in
Timber
Mining
Loss of livestock
Camping safety 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
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 research and education
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. 5. Fertilizer runoff can result in the _________ of lakes.
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 _________.
1. Fragmentation 2. greenhouse migrate eutrophication sustainable tropics
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. 14. The Earth is facing a serious _________ crisis.
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.
8. Magnification habitat biodiversity ESA plants population
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. The Evolution of Animals
Reading Assignment for:
Next week, 12/4/07 & 12/6/07
Chapter 17
The Evolution of Animals