Ecosystems, Energy, and Trophic Pyramids

1. Ecosystems, Energy, and Trophic Pyramids

2. Ecosystems And Energy Energy Laws of Thermodynamics Photosynthesis/Respiration Trophic Pyramids Energy Flow Food Webs Productivity

3. Examples of Possible Exam Questions • Explain what a pyramid of energy represents, define the second law of thermodynamics, and relate how the shape of a pyramid of energy is due, in part, to the second law of thermodynamics. • Diagram a trophic pyramid. Label each block of the pyramid with the term describing those organisms. .

4. Examples of Possible Exam Questions 3. Explain the process of Biological Magnification. In your explanation, provide an example of biological magnification. • Explain what a food web is and discuss insights into species importance that are gained by understanding food webs. • Explain what a trophic pyramid is and discuss insights that are gained by understanding trophic structure..

5. Inductive And Deductive Reasoning • Inductive reasoning begins with specific observations and ends with a conclusion that goes beyond any of the observations that led up to the conclusion. (Based on probabilities) • Deductive reasoning begins with a generalization and uses logic to create a conclusion.

6. Inductive Reasoning • A form of reasoning in which a conclusion is reached based on a pattern present in numerous observations. • In inductive reasoning you draw a conclusion based on specific evidence. The conclusion may be more or less likely, but it is not necessarily true. • Most often used in science and law.

7. Example of Inductive Reasoning • Between 1850 and 1930, measurements of the population size showed that each time the populations of Snowshoe hares increased or decreased the populations of lynx also increased or decreased. • The conclusions are that the populations of Snowshoe hares and lynx depend upon each other.

8. Deductive Reasoning • A form of reasoning in which evidence or observations are secondary. • In deductive reasoning the concern is to define a commonly accepted VALUE or BELIEF that prepares the way for the argument you want to make.

9. Deductive Reasoning • In deductive reasoning the conclusion is that something must be true because it is a special case of a general principle that is known to be true. • Based upon two premises and a conclusion (syllogism). Logically, the conclusion is true if the premises are true.

10. Example of Deductive Reasoning • Premise one: If Sarah is ten feet tall, she can dunk a basketball. • Premise two: Sarah is ten feet tall. • Conclusion: Sarah can dunk a basketball. Valid conclusion

11. Example of Deductive Reasoning • Premise one: If Sarah is ten feet tall, she can dunk a basketball. • Premise two: Sarah can dunk a basketball. • Conclusion: Sarah is ten feet tall. Invalid conclusion

12. Example of Deductive Reasoning • Premise one: If there is fog the plane will be diverted. • Premise two: There is no fog. • Conclusion: The plane will not be diverted. Valid or invalid conclusion?

13. Ecology • The study of relationships between organisms and their environment. • Environment= biotic and abiotic factors that affect an organism during its lifetime. • Abiotic factors:nonliving parts of the environment - water, minerals, sunlight, climate. • Biotic factors:organisms that are a part of the environment

15. Laws of Thermodynamics First Law (Conservationof Energy) Energy is neither created nor destroyed; it is always conserved. Second Law Energy always tends to go from a more usable form to a less usable form, so the amount of energy available to do work decreases (entropy occurs).

17. Consequence Of Laws Of Thermodynamics For Living Organisms Organisms require a constant input of energy to maintain a high level of organization.

18. Types of Energy Systems

19. Photosynthesis (Transformation of Light Energy) 6 CO2 + 12 H2O + radiant energy C6H12O6+ 6 H2O + 6 O2 Stores energy in chemical bonds

20. Respiration (Transformation of Chemical Energy) C6H12O6 + 6 H2O + 6 O2 6 CO2 +12 H2O + energy Provides energy for “work”

21. Ecological Studies Show How the Whole System Works. • Focus: • The roles played by members of a community • 2. The energy/resource structure of the system.

22. Ecosystem Organization Each system can help clarify different issues. 1. Trophic Pyramids 2. Food Webs 3. Nutrient Cycles

23. (Autotrophs and Heterotrophs)

27. Pyramids of Energy Suggests: • 1. The number of trophic levels are limited. At each trophic level, there is a dramatic reduction in energy. • 2. Eating at lower trophic levels means more resources are available.

29. Pyramids of Energy Suggests: 1. The number of trophic levels are limited. At each trophic level, there is a dramatic reduction in energy. • 2. Eating at lower trophic levels means more resources available. • 3. Movement up the pyramid explains the problems of Biological Magnification (DDT, PCBs, etc.)

30. Biological Magnification • Concentration of a compound can increase at higher trophic levels because each individual in a higher trophic level must eat many individuals of a lower trophic level to survive. • Although the energy acquired by eating those organisms from a lower trophic level is used, the toxic compounds may remain (Especially true for compounds that are stored in fats and are not easily broken down.).

32. Food webs • Are interlocking food chains based on which organisms eat which. • Arrows show the direction of food/energy flow

33. Ecological Pyramids • Pyramid of energy • Pyramid of numbers • Pyramid of biomass • Gross Primary Productivity= total amount of energy captured by photosynthesis for an ecosystem.

34. Keystone Species Food webs suggest that keystone species may be important. Changes in one species may dramatically change the entire ecosystem through links in the web. Keystone Species = Species whose presence is essential to community function and stability (e.g., Krill in Antarctica).