1. Lesson 5: Biological Diversity Big Question Big Question: Can We Save Endangered Species and Keep Biological Diversity High?

2. Lesson 5/ ESRM 100 / University of Washington What Is Biological Diversity? Biological diversity is the wealth of species that live on Earth Commonly expressed as the number of species or genetic types in an area

3. Lesson 5/ ESRM 100 / University of Washington Biological Evolution An important question about biological diversity is "How did it all come about?" In the 19th century, Charles Darwin proposed an explanation that became known as biological evolution It is the change in inherited characteristics of a population from generation to generation Ultimately, it can result in new species

4. Lesson 5/ ESRM 100 / University of Washington Mutation Deoxyribonucleic acid (DNA) carries inherited information from one generation of cells to the next The chemical information for a single characteristic is a gene The genetic makeup of an individual or group is a genotype

5. Lesson 5/ ESRM 100 / University of Washington Selection Change is not always for the better. Mutation can result in a new species whether or not that species is better adapted to the environment than its parent species. Individuals with characteristics making them better able to survive and reproduce leave more offspring than others; they are more fit. This process of increasing the proportion of better-adapted offspring is natural selection.

6. Lesson 5/ ESRM 100 / University of Washington Migration Geographic isolation can lead to divergent evolution. The two populations may change so much that they can no longer reproduce together.

7. Lesson 5/ ESRM 100 / University of Washington Genetic Drift Sometimes changes in genetic makeup of a population occur simply from chance: drift. Genetic drift can be a problem for rare or endangered species. Lower fitness traits may dominate. Small size of the population reduces genetic variability.

8. Lesson 5/ ESRM 100 / University of Washington Island Ecology Islands have fewer species than continents, and the smaller the island, the fewer the species, on average. Also, the farther away an island is from a continent, the fewer species it will have.

9. Lesson 5/ ESRM 100 / University of Washington Adaptive Radiation Isolation on remote islands can lead to adaptive radiation. An example is Hawaiian Honeycreepers.

10. Lesson 5/ ESRM 100 / University of Washington Basic Concepts of Biological Diversity

11. Lesson 5/ ESRM 100 / University of Washington How many Species on Earth? See the Wikipedia article on Species.Species www.wildlifeinstitute.org/press_gallery.htm http://www.worldproutassembly.org/

12. Lesson 5/ ESRM 100 / University of Washington How many Species on Earth?

13. Lesson 5/ ESRM 100 / University of Washington What Can We Do to Save Endangered Species? How many species are threatened with extinction? According to the IUCN Red Book of Threatened Species 23% of mammals, 12% of birds, 4% of reptiles, 31% of amphibians, and 3% of fish; and 3% of plants.

14. Lesson 5/ ESRM 100 / University of Washington Endangered and Threatened Species What does it mean to call a species endangered or threatened? Endangered species means any species which is in danger of extinction throughout all or a significant portion of its range. Threatened species means any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.

15. Lesson 5/ ESRM 100 / University of Washington Why Save Endangered Species? Taken from http://www.fws.gov/endangered/

16. Lesson 5/ ESRM 100 / University of Washington How a Species Becomes Endangered and Extinct Extinction is the rule of nature Local extinction is when a species disappears from a part of its range Global extinction is when a species can no longer be found anywhere Rates of extinctions have varied greatly over geologic time

17. Lesson 5/ ESRM 100 / University of Washington Mass Extinctions The fossil record suggests that there have been several periods of mass extinction and other periods of rapid evolution of new species

18. Lesson 5/ ESRM 100 / University of Washington Causes of Mass Extinction Six major mass extinctions occurred during the past 550 million years The end of the dinosaurs about 65 million years ago – asteroid impact? Megafauna extinctions 20,000–10,000 years ago at the end of the last great continental glaciation period The rate of extinctions has increased greatly since the Industrial Revolution

19. Lesson 5/ ESRM 100 / University of Washington How People Cause Extinctions and Affect Biological Diversity Some ways we cause extinction: hunting or harvesting disrupting or eliminating habitats introducing exotic species polluting

20. Lesson 5/ ESRM 100 / University of Washington The Good News: The Status of Some Species Has Improved Success stories include Elephant seals; Sea otters; Recovery of bird populations after the ban on DDT; and Blue and gray whales. Link: "Living with alligators: A Florida reality" at http://edis.ifas.ufl.edu/UW230

21. Chapter 5: Biological Diversity Questions? E-mail your TA. eschelp@u.washington.edu