Exploring Ecology: Interactions and Distribtions in Biospheres

1. Chapter 50 An Introduction to Ecology and the Biosphere

2. Concept 50.1: • Ecology is the study of interactions between organisms and the environment

3. Organisms and the Environment • The environment of any organism includes • Abiotic, or nonliving components • Biotic, or living components • All the organisms living in the environment, the biota

4. Climate in northern Australia is hot and wet, with seasonal drought. Kangaroos/km2 > 20 10–20 5–10 1–5 0.1–1 Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year. < 0.1 Limits ofdistribution Southeastern Australia has a wet, cool climate. Southern Australia has cool, moist winters and warm, dry summers. Tasmania Environmental components • Affect the distribution and abundance of organisms Figure 50.2

5. Ecologists • Use observations and experiments to test explanations for the distribution and abundance of species

6. (a) Organismal ecology. How do humpback whales select their calving areas? Subfields of Ecology • Organismal ecology • Studies how an organism’s structure, physiology, and (for animals) behavior meet the challenges posed by the environment Figure 50.3a

7. Population ecology. What environmental factors affect the reproductive rate of deer mice? (b) • Population ecology • Concentrates mainly on factors that affect how many individuals of a particular species live in an area Figure 50.3b

8. Community ecology • Deals with the whole array of interacting species in a community (c) Community ecology.What factors influencethe diversity of speciesthat make up aparticular forest? Figure 50.3c

9. Ecosystem ecology • Emphasizes energy flow and chemical cycling among the various biotic and abiotic components (d) Ecosystem ecology. Whatfactors control photosyntheticproductivity in a temperategrassland ecosystem? Figure 50.3d

10. (e) Landscape ecology. To what extent do the trees lining the drainage channels in this landscape serve as corridors of dispersal for forest animals? • Landscape ecology • Deals with arrays of ecosystems and how they are arranged in a geographic region Figure 50.3e

11. The biosphere • Is the global ecosystem, the sum of all the planet’s ecosystems

12. Figure 50.4 Ecology and Environmental Issues • Ecology • Provides the scientific understanding underlying environmental issues • Rachel Carson • Is credited with starting the modern environmental movement

13. Concept 50.2: • Interactions between organisms and the environment limit the distribution of species

14. Dispersal and Distribution • Dispersal • Is the movement of individuals away from centers of high population density or from their area of origin • Contributes to the global distribution of organisms

15. New areasoccupied Year 1996 1989 1974 Natural Range Expansions • Natural range expansions • Show the influence of dispersal on distribution Figure 50.7

16. Species Transplants • Species transplants • Include organisms that are intentionally or accidentally relocated from their original distribution • Can often disrupt the communities or ecosystems to which they have been introduced

17. Behavior and Habitat Selection • Some organisms • Do not occupy all of their potential range • Species distribution • May be limited by habitat selection behavior

18. Biotic Factors • Biotic factors that affect the distribution of organisms may include • Interactions with other species • Predation • Competition

19. W. J. Fletcher tested the effects of two algae-eating animals, sea urchins and limpets, on seaweed abundance near Sydney, Australia. In areas adjacent to a control site, either the urchins, the limpets, or both were removed. EXPERIMENT Fletcher observed a large difference in seaweed growth between areas with and without sea urchins. RESULTS Removing bothlimpets andurchins orremoving onlyurchins increasedseaweed coverdramatically. 100 Seaurchin Both limpetsand urchinsremoved 80 Onlyurchinsremoved 60 Seaweed cover (%) Limpet 40 Almost noseaweed grew in areas whereboth urchins andlimpets werepresent, or whereonly limpets wereremoved. Only limpets removed Control (bothurchins andlimpets present) 20 0 February 1984 February 1983 August 1983 August 1982 Removing both limpets and urchins resulted in the greatest increase of seaweed cover, indicating that bothspecies have some influence on seaweed distribution. But since removing only urchins greatly increased seaweed growth whileremoving only limpets had little effect, Fletcher concluded that sea urchins have a much greater effect than limpets in limitingseaweed distribution. CONCLUSION An Ecological Experiment Figure 50.8

20. Abiotic Factors • Abiotic factors that affect the distribution of organisms may include • Temperature • Water • Sunlight • Wind • Rocks and soil

21. Climate • Four major abiotic components make up climate • Temperature, water, sunlight, and wind • Climate • Is the prevailing weather conditions in a particular area

22. Regional, Local, and Seasonal Effects on Climate • Various features of the landscape • Contribute to local variations in climate

23. Warm air over land rises. 1 Cooler air sinks over water. 3 Air cools at high elevation. 2 Cool air over water moves inland, replacing rising warm air over land. 4 Bodies of Water • Oceans and their currents, and large lakes • Moderate the climate of nearby terrestrial environments Figure 50.11

24. As moist air moves in off the Pacific Ocean and encounters the westernmost mountains, it flows upward, cools at higher altitudes, and drops a large amount of water. The world’s tallest trees, the coastal redwoods, thrive here. 1 Farther inland, precipitation increases again as the air moves up and over higher mountains. Some of the world’s deepest snow packs occur here. 2 On the eastern side of the Sierra Nevada, there is little precipitation. As a result of this rain shadow, much of central Nevada is desert. 3 Wind direction East PacificOcean Sierra Nevada CoastRange Figure 50.12 Mountains • Mountains have a significant effect on • The amount of sunlight reaching an area • Local temperature • Rainfall

25. Microclimate • Microclimate • Is determined by fine-scale differences in abiotic factors

26. Concept 50.3: • Varying combinations of both biotic and abiotic factors • Determine the nature of Earth’s many biomes • Biomes • Broad geographic regions defined by their biotic and abiotic associations

27. 30N Tropic of Cancer Equator Continentalshelf Tropic of Capricorn 30S Key Rivers Abyssal zone(below oceanicpelagic zone) Lakes Estuaries Intertidal zone Coral reefs Oceanic pelagiczone Earth’s aquatic biomes Figure 50.15

28. LAKES An oligotrophic lake in Grand Teton, Wyoming A eutrophic lake in Okavango delta, Botswana Lakes Figure 50.17

29. WETLANDS Okefenokee National Wetland Reserve in Georgia Wetlands Figure 50.17

30. STREAMS AND RIVERS A headwater stream in theGreat Smoky Mountains The Mississippi River farform its headwaters Streams and rivers Figure 50.17

31. ESTUARIES An estuary in a low coastal plain of Georgia Estuaries Figure 50.17

32. INTERTIDAL ZONES Rocky intertidal zone on the Oregon coast Intertidal zones Figure 50.17

33. OCEANIC PELAGIC BIOME Open ocean off the island of Hawaii Oceanic pelagic biome Figure 50.17

34. CORAL REEFS A coral reef in the Red Sea Coral reefs Figure 50.17

35. MARINE BENTHIC ZONE A deep-sea hydrothermal vent community Marine benthic zone Figure 50.17

36. Concept 50.4: • Climate • Is particularly important in determining why particular terrestrial biomes are found in certain areas

37. Temperate grassland Desert Tropical forest 30 Temperate broadleaf forest 15 Annual mean temperature (ºC) Coniferous forest 0 Arctic and alpine tundra 15 100 200 300 400 Annual mean precipitation (cm) Climate and Terrestrial Biomes • This climograph shows the relationship between different biomes and two climatic factors. Figure 50.18

38. 30N Tropic of Cancer Equator Tropic of Capricorn 30S Chaparral Tundra Key Temperate grassland High mountains Tropical forest Temperate broadleaf forest Polar ice Savanna Coniferous forest Desert The distribution of major terrestrial biomes Figure 50.19

39. TROPICAL FOREST Figure 50.20 A tropical rain forest in Borneo Tropical forest

40. DESERT Figure 50.20 The Sonoran Desert in southern Arizona Desert

41. SAVANNA A typical savanna in Kenya Savanna Figure 50.20

42. CHAPARRAL An area of chaparral in California Chaparral Figure 50.20

43. TEMPERATE GRASSLAND Sheyenne National Grassland in North Dakota Figure 50.20 Temperate grassland

44. CONIFEROUS FOREST Rocky Mountain National Park in Colorado Coniferous forest Figure 50.20

45. TEMPERATE BROADLEAF FOREST Great Smoky Mountains National Park in North Carolina Temperate broadleaf forest Figure 50.20

46. Tundra TUNDRA Figure 50.20 Denali National Park, Alaska, in autumn