1. The Flow of Energy in Ecosystems

2. Three Factors Sustain Life on Earth
One-way flow of high-quality energy beginning with the sun
Cycling of matter or nutrients
Gravity

3. Some Types of Energy Are More Useful Than Others
Energy Quality: a measure of energy’s capacity to do useful work
High-quality energy
High temperature heat
nuclear fission, concentrated sunlight, energy released by burning fossil fuels
Low-quality energy
Heat dispersed in the air or oceans 3

4. Some Forms of Matter Are More Useful than Others
High-quality matter
Low-quality matter 4

5. Energy Changes Are Governed by Two Scientific Laws
First Law of Thermodynamics
Energy input always equals energy output
ENERGY CANNOT BE CREATED OR DESTROYED
Second Law of Thermodynamics
Energy always goes from a more useful to a less useful form when it changes from one form to another 5

6. * Chemistry Review: Law of conservation of matter Matter consumption
We Cannot Create or Destroy Matter
Matter consumption
Matter is converted from one form to another 6

7. The Second Law of Thermodynamics in Living Systems7

8. Active Figure: Energy flow

9. 3-3 What Are the Major Components of an Ecosystem?
Concept 3-3A Ecosystems contain living (biotic) and nonliving (abiotic) components.
Concept 3-3B Some organisms produce the nutrients they need, others get their nutrients by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms. 9

10. Ecosystems Have Living and Nonliving Components
Abiotic: the non-living components of the world
Water
Air
Nutrients
Rocks
Heat
Solar energy
Biotic: The living (or once living) components of the world
Plants, Animals… you get the idea 10

11. Major Biotic and Abiotic Components of an Ecosystem11

12. Producers and Consumers Are the Living Components of Ecosystems (1)
Producers, autotrophs: make their own food
Photosynthesis
Chemosynthesis
Consumers, heterotrophs: must feed on other organisms
Primary
Secondary
Third and higher level 12

13. Producers and Consumers Are the Living Components of Ecosystems (2)
More Consumers
Decomposers: digests parts of dead organisms or cast-off fragments & wastes of living organisms *mode of eating is to absorb soluble nutrients
Detritivores: digests parts of dead organisms or cast-off fragments & wastes of living organisms *mode of eating is “chomp chomp”
Aerobic respiration: breakdown of glucose WITH oxygen
Anaerobic respiration, fermentation: breakdown of glucose WITHOUT oxygen 13

14. Detritivores and Decomposers on a Log14

15. 3-4 What Happens to Energy in an Ecosystem?
Concept 3-4A Energy flows through ecosystems in food chains and webs.
Concept 3-4B As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases. 15

16. The Main Structural Components of an Ecosystem16

17. Energy Flows Through Ecosystems in Food Chains and Food Webs
Series of organisms in which each eats or decomposes the preceding one
Food web
Complex network of many interconnected food chains 17

18. A Food Chain 18

19. Simplified Food Web in the Antarctic19

20. Active Figure: Categories of food webs

21. Usable Energy Decreases with Each Link in a Food Chain or Web
Biomass
The total dry weight of all living organisms
Ecological efficiency
The percentage of energy transferred from one trophic level to another in a food chain or food web
Pyramid of energy flow
A diagram representing the flow of energy through each trophic level in a food chain or food web.
With each transfer, only about 10% of the usable energy is transferred to the organism at the next trophic level 21

22. Pyramid of Energy Flow 22

23. Some Ecosystems Produce Plant Matter Faster Than Others Do
Gross primary productivity (GPP)
The rate at which producers capture and store chemical energy as biomass
Net primary productivity (NPP)
The total energy stored by the producers, minus the energy they use for respiration
Ecosystems and life zones differ in their NPP 23

24. Estimated Annual Average NPP in Major Life Zones and Ecosystems24

25. 2-5 What Are Systems and How Do They Respond to Change?
Concept 2-5A Systems have inputs, flows, and outputs of matter and energy, and their behavior can be affected by feedback.
Concept 2-5B Life, human systems, and the earth’s life support systems must conform to the law of conservation of matter and the two laws of thermodynamics. 25

26. Systems Have Inputs, Flows, and Outputs
System: set of components that function and interact in some regular and theoretically predictable manner
Inputs from the environment
Flows, throughputs
Outputs 26

27. Inputs, Throughput, and Outputs of an Economic System27

28. Systems Respond to Change through Feedback Loops
Positive feedback loop: feedback loop that causes a system to change further in the same direction
Negative, or corrective, feedback loop: feedback loop that causes a system to change in the opposite direction from which it is moving 28

29. Positive Feedback Loop29

30. Negative Feedback Loop30

31. Time Delays Can Allow a System to Reach a Tipping Point
Time delays vary
Between the input of a feedback stimulus and the response to it
Tipping point
Threshold level at which an environmental problem causes a fundamental and irreversible shift in the behavior of a system 31

32. System Effects Can Be Amplified through Synergy
Synergistic interaction, synergy
Interaction of two or more factors or processes so that the combined effect is greater than the sum of their separate effects
Helpful
E.g., a letter writing campaign/petition
Harmful
E.g., Smoking and inhaling asbestos particles 32

33. Animation: Feedback control of temperature

34. Human Activities Can Have Unintended Harmful Results
Deforested areas turning to desert
Coral reefs dying
Glaciers melting
Sea levels rising 34