Interdependence: A Key Theme in Ecology

1. Problem Set 2-1: Visual Metaphor Chapter 18 Interdependence: A Key Theme in Ecology • Organisms and Their Environments • Species interact with both other species and their nonliving environment. • Interdependence is a theme in ecology—one change can affect all species in an ecosystem.

3. Section 1 Introduction to Ecology Chapter 18 Levels of Organization in studying an ecological system • Ecologists recognize a hierarchy of organization in the environment: biosphere, ecosystem, community, population, and organism.

4. Section 1 Introduction to Ecology Chapter 18 Levels of Organization

5. Section 1 Introduction to Ecology Chapter 18 Levels of Organization, continued • The Biosphere • The broadest, most inclusive level of organization is thebiosphere,the thin volume of Earth and its atmosphere that supports life. • All organisms are found in the biosphere • Extends from ~ 5-6 miles above earth to the deepest part of the oceans.

6. Section 1 Introduction to Ecology Chapter 18 Levels of Organization, continued • Ecosystems • The biosphere is composed of smaller units called ecosystems. • An ecosystemincludes all of the organisms and the nonliving environment found in a particular place. • BIOTIC FACTORS--A pond ecosystem includes all of the fish, turtles, insects, aquatic plants, algae and bacteria (all living things)

7. Section 1 Introduction to Ecology Chapter 18 Ecosystem • ABIOTIC FACTORS--A pond ecosystem also includes all of the physical and chemical aspects of the pond that influence its inhabitants. • ie pH, levels of dissolved oxygen, carbon dioxide, nitrogen as well as the amount of sunlight. Temperature, humidity, salinity, precipitation

9. Section 1 Introduction to Ecology Chapter 18 Levels of Organization, continued • Communities, Populations, and Organisms • Acommunityis all the interacting organisms living in an area. • Below the community level of organization is thepopulationlevel,where the focus is on the individual organisms of a single species. • Size, density, and dispersion are characteristics of populations

10. Section 1 Introduction to Ecology Chapter 18 Community

11. Population Growth Logistic vs Exponential- Logistic limited by resources Exponential steady growth rate Exponential Logistic

12. Section 2 Ecology of Organisms Chapter 18 Objectives • Compareabiotic factors with biotic factors, and list two examples of each. • Describetwo mechanisms that allow organisms to survive in a changing environment. • Explainthe concept of the niche.

13. Section 2 Ecology of Organisms Chapter 18 Ecosystem Components • Biotic and Abiotic Factors • Bothbiotic, or living, factors andabiotic, or nonliving, factors influence organisms. Examples of abiotic factors are climate, sunlight, and pH.

14. Section 2 Ecology of Organisms Chapter 18 The Niche • A nicheis a way of life, or a role (What’s your job?) in an ecosystem. • Range of conditions the organism can tolerate • The resources it uses • Method of obtaining resources • Number of offspring • Time of reproduction • All interactions with its environment

15. Section 2 Ecology Of Organisms Chapter 18 Earthworm Niche

17. Section 3 Energy Transfer Chapter 18 Objectives • Summarizethe role of producers in an ecosystem. • Identifyseveral kinds of consumers in an ecosystem. • Explainthe important role of decomposers in an ecosystem. • Comparethe concept of a food chain with that of a food web. • Explainwhy ecosystems usually contain only a few trophic levels.

18. Section 3 Energy Transfer Chapter 18 Producers • Most producersare photosynthetic and make carbohydrates by using energy from the sun.

19. Section 3 Energy Transfer Chapter 18 Producers, continued • Measuring Productivity • Gross primary productivityis the rate at which producers in an ecosystem capture the energy of sunlight by producing organic compounds. • The rate at which biomass accumulates is callednet primary productivity.

20. Section 3 Energy Transfer Chapter 18 Consumers • Consumersobtain energy by eating other organisms and include herbivores, omnivores, carnivores, detritivores, and decomposers.

21. Section 3 Energy Transfer Chapter 18 Comparing Consumers and Producers

22. Section 3 Energy Transfer Chapter 18 Energy Flow • When one organism eats another, organic molecules are metabolized and energy transferred. • Food Chains and Food Webs • A single pathway of energy transfer is afood chain. • A network showing all paths of energy transfer is a food web.

23. Section 3 Energy Transfer Chapter 18 Food Chains and Food Webs

24. Section 3 Energy Transfer Chapter 18 Food Chain in an Antarctic Ecosystem

25. Section 3 Energy Transfer Chapter 18 Food Web in an Antarctic Ecosystem

26. Section 3 Energy Transfer Chapter 18 Energy Flow, continued • Energy Transfer • Ecosystems contain only a few trophic levels because there is a low rate of energy transfer between each level. • ~10% of energy is transferred to the next trophic level • Some organisms in one trophic level escape being eaten • When they die, they are eaten by decomposers, but the energy does not go to a higher trophic level • Energy transfer is never 100 % efficient when changing form • There are many more organisms in lower trophic levels because higher levels contain less energy and can not support as many organisms. • Trophic level = feeding level in an ecosystem

27. Section 3 Energy Transfer Chapter 18 Energy Transfer Through Trophic Levels There are about 1000 zebras for every lion. There are many grasses.

28. Section 3 Energy Transfer Chapter 18 Energy Pyramid

29. Section 4 Ecosystem Recycling Chapter 18 Objectives • Listfour major biogeochemical cycles. • Summarizethree important processes in the water cycle. • Outlinethe major steps in the carbon cycle. • Describethe role of decomposers in the nitrogen cycle. • Summarizethe major steps of the phosphorus cycle.

31. Since stratospheric ozone is produced by solar UV radiation, one might expect to find the highest ozone levels over the tropics and the lowest over polar regions. The same argument would lead one to expect the highest ozone levels in the summer and the lowest in the winter. The observed behavior is very different: most of the ozone is found in the mid-to-high latitudes of the northern and southern hemispheres, and the highest levels are found in the spring, not summer, and the lowest in the autumn, not winter in the northern hemisphere The ozone layer can be depleted by free radical catalysts, including nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br).

32. Section 4 Ecosystem Recycling Chapter 18 The Water Cycle • Key processes in thewatercycleare evaporation, transpiration, and precipitation. • Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants (similar to sweating), especially in leaves (stomata) but also in stems.

33. Section 4 Ecosystem Recycling Chapter 18 Water Cycle

34. Section 4 Ecosystem Recycling Chapter 18 Water Cycle

35. Section 4 Ecosystem Recycling Chapter 18 The Carbon Cycle • Photosynthesis and cellular respiration are the two main steps in thecarbon cycle.

36. Section 4 Ecosystem Recycling Chapter 18 Carbon Cycle

37. Section 4 Ecosystem Recycling Chapter 18 Carbon Cycle

38. In the last 150 years the concentration of atmospheric carbon dioxide has risen more than 30%. This has increased the temperature about 1⁰C since 1900.

39. Section 4 Ecosystem Recycling Chapter 18 Nitrogen Cycle • N2 gas makes up 78% of the atmosphere, but plants cannot use nitrogen unless it is in the form of nitrate. • Nitrogen-fixing bacteriaare important in thenitrogen cyclebecause they change nitrogen gas into this usable form of nitrogen for plants-nitrogen fixation. • The plants supply carbohydrates to the bacteria.

40. Section 4 Ecosystem Recycling Chapter 18 Nitrogen Cycle

41. Section 4 Ecosystem Recycling Chapter 18 Nitrogen Cycle

42. Section 4 Ecosystem Recycling Chapter 18 Phosphorus Cycle • In thephosphorus cycle,phosphorus moves from phosphate deposited in rock, to the soil, to living organisms, and finally to the ocean.

43. Chapter 18 Standardized Test Prep Multiple Choice 1. What are the levels of organization in ecology? A. cell, tissue, organ, organ system, body B. organ, organism, population, community C. organism, population, community, ecosystem, biosphere D. population, habitat, ecosystem, biogeochemical system, planet

44. Chapter 18 Standardized Test Prep Multiple Choice, continued 1. What are the levels of organization in ecology? A. cell, tissue, organ, organ system, body B. organ, organism, population, community C. organism, population, community, ecosystem, biosphere D. population, habitat, ecosystem, biogeochemical system, planet

45. Chapter 18 Standardized Test Prep Multiple Choice, continued 2. What makes up an ecosystem? F. all the habitat types on Earth G. all parts of Earth where life exists H. all members of a species in the same area J. all the living and nonliving factors in an environment

46. Chapter 18 Standardized Test Prep Multiple Choice, continued 2. What makes up an ecosystem? F. all the habitat types on Earth G. all parts of Earth where life exists H. all members of a species in the same area J. all the living and nonliving factors in an environment

47. Chapter 18 Standardized Test Prep Multiple Choice, continued 3. Which of the following are abiotic factors? A. plants B. animals C. sunlight D. microorganisms

48. Chapter 18 Standardized Test Prep Multiple Choice, continued 3. Which of the following are abiotic factors? A. plants B. animals C. sunlight D. microorganisms

49. Chapter 18 Standardized Test Prep Multiple Choice, continued 4. How do decomposers benefit an ecosystem? F. by returning nutrients to the soil G. by manufacturing energy from sunlight H. by removing excess nutrients from the soil J. by removing predators from the ecosystem

50. Chapter 18 Standardized Test Prep Multiple Choice, continued 4. How do decomposers benefit an ecosystem? F. by returning nutrients to the soil G. by manufacturing energy from sunlight H. by removing excess nutrients from the soil J. by removing predators from the ecosystem