Species Interactions

1. Species Interactions HUMANS IN THE BIOSPHERE CHAPTER 6

2. ADAPTED FROM BBC ARTICLE by Alex Kirby Biodiversity and Extinction: The sixth great wave

3. All the creatures we share the Earth with are important in some way, however unprepossessing or insignificant they may appear. They and we are all part of the web of life.

4. From the dawn of time, extinction has usually progressed at what scientists call a natural or background rate. Today the tempo is far faster.

5. Many scientists believe this is the sixth great wave - the sixth mass extinction to affect life on Earth. • FIVE MASS EXTINCTIONS • Cretaceous (About 65 million years ago) • Triassic (About 208 million years ago) • Permian (About 245 million years ago) • Devonian (About 360 million years ago) • Ordovician (About 438 million years ago)

7. Human Population Growth • We have more than doubled our numbers in half a century, and that is the most obvious reason why there is less room for any other species

8. We are taking their living room to grow our food, their food to feed ourselves. We are exploiting them, trading in them, squeezing them to the margins of existence - and beyond.

9. LIVING PLANET INDEX

10. LIVING PLANET INDEX • The index tracks the size of specific populations of selected species • It shows them as a percentage of the 1970 populations • It shows falling population levels in all three ecosystem types studied

11. Often the choice is hard: conserve a species or feed a community, tourists' dollars or turtles' nests

12. Facts In 2003 the World Conservation Union's Red List said more than 12,000 species (out of 40,000 assessed) faced some extinction risk, including: • one bird in eight • 13% of the world's flowering plants • a quarter of all mammals.

13. Why is biodiversity important? • Many species keep us alive, purifying water, fixing nitrogen, recycling nutrients and waste, and pollinating crops. • Plants and bacteria carry out photosynthesis, which produces the oxygen we breathe. Trees absorb carbon dioxide, the main greenhouse gas given off by human activities.

14. Contributions lost • Tropical cone snails contain toxins which show promise for treating some forms of cancer and heart irregularities. One toxin may be a thousand times more potent than morphine for pain relief. • Millions of cone snails are now killed annually for their shells, and their habitats are under pressure.

15. Contributions lost • Brazil nuts are a lucrative harvest in the Amazon. But an experiment to produce them in plantations failed, because the trees bear a good crop in the forest, but are barren in isolation. • US researchers estimate that by 2020 less than 5% of the Amazon will remain in pristine condition.

16. Amazon Deforestationhttp://geography.uoregon.edu/bartlein/animations/rondonia.gifAnimation show 1982 to 1992

17. Contributions lost • Within 15 years, about a fifth of central Africa's forests will have gone • 71% of UK butterfly species are reported to be declining

18. Humans are bucking the trend towards extinction. In 1953 there were about 2.5bn people: today there are 6bn.

19. Population Pressure: Hawaii • Stressed physiological conditions may threaten the health and sustainability of coral reefs

20. Extinction versus Endangered • Extinction is forever • Endangered = still time • Biodiversity Video

21. US Department of Fish and Game,Endangered Species Division • Listing Status • Endangered • Critically Endangered • Threatened • Rare • http://www.fws.gov/endangered/wildlife.html#Species

22. Ecological IssuesWhat do you know about the following? • Global Warming “Greenhouse Effect” • Caused by • _______is trapped between the ____________ and the earth. • Problems? • Ozone Depletion • Caused by the__________________________________________ which remove ____________________________________________________. • Problems? • Acid Rain • Burning _____________________________ produces SO2 and NOx • They mix with water forming • Problems?

23. Ecological Issues • Global Warming “Greenhouse Effect” • Caused by the accumulation of CO2 and CH4 • Heat is trapped between the CO2 layer and the earth. • Problems? • Solution? http://www.androidworld.com/prod60.htm

25. Ecological Issues B. Ozone Depletion • Caused by the CFC’s (Chloroflurocarbons) removing ozone molecules from the atmosphere. • Problems? – UV light allowed in! • CFC’s banned in 1980’s – the result is positive as some scientists predict the holes may shrink and disappear in approx. 50 yrs

28. Ecological Issues C. Acid Rain • Burning fossil fuels produces SO2 and NOx • They mix with water forming Sulfuric Acid (H2SO4) making the rain acidic. • Problems?

30. Figure 6-16 Biological Magnification of DDT Section 6-3 Magnification of DDT Concentration Fish-Eating Birds 10,000,000 Large Fish 1,000,000 Small Fish 100,000 Zooplankton 10,000 Producers 1000 Water 1

31. Biological Magnification • Harmful pollutants become more concentrated as they make there way up the food pyramid

32. California connection: mercury magnification CA history link

33. Succession • Two Types • Primary succession • Secondary succession

34. Primary Succession - begins in barren areas, such as on bare rock exposed by a retreating glacier. The first inhabitants are lichens or plants—those that can survive in such an environment. Over hundreds of years these “pioneer species” convert the rock into soil that can support simple plants such as grasses. These grasses further modify the soil, which is then colonized by other types of plants. Each successive stage modifies the habitat by altering the amount of shade and the composition of the soil. The final stage of succession is a climax community, which is a very stable stage that can endure for hundreds of years.

35. Secondary succession