Ecosystems, Energy, and Trophic PyramidsEcosystems, Energy, and Trophic Pyramids

Ecosystems And EnergyEcosystems And Energy

EnergyEnergyLaws of ThermodynamicsLaws of ThermodynamicsPhotosynthesis/RespirationPhotosynthesis/Respiration

Trophic PyramidsTrophic Pyramids

Energy FlowEnergy Flow

Food WebsFood Webs

ProductivityProductivity

Examples of Possible Exam QuestionsExamples of Possible Exam Questions

1.1. Explain what a pyramid of energy represents, Explain what a pyramid of energy represents, define the second law of thermodynamics, and define the second law of thermodynamics, and relate how the shape of a pyramid of energy is relate how the shape of a pyramid of energy is due, in part, to the second law of due, in part, to the second law of thermodynamics.thermodynamics.

2. Diagram a trophic pyramid. Label each block of the pyramid with the term describing those organisms.

.

Examples of Possible Exam QuestionsExamples of Possible Exam Questions

3.3. Explain the process of Explain the process of Biological MagnificationBiological Magnification. . In your explanation, provide an example of In your explanation, provide an example of biological magnification.biological magnification.

4.4. Explain what a food web is and discuss insights Explain what a food web is and discuss insights into species importance that are gained by into species importance that are gained by understanding food webs. understanding food webs.

5.5. Explain what a trophic pyramid is and discuss Explain what a trophic pyramid is and discuss insights that are gained by understanding trophic insights that are gained by understanding trophic structure.structure..

Inductive And Deductive ReasoningInductive And Deductive Reasoning

• Inductive reasoning begins with specific Inductive reasoning begins with specific observations and ends with a conclusion observations and ends with a conclusion that goes beyond any of the observations that goes beyond any of the observations that led up to the conclusion. (Based on that led up to the conclusion. (Based on probabilities)probabilities)

• Deductive reasoning begins with a Deductive reasoning begins with a generalization and uses logic to create a generalization and uses logic to create a conclusion.conclusion.

Inductive ReasoningInductive Reasoning

• A form of reasoning in which a conclusion is A form of reasoning in which a conclusion is reached based on a pattern present in reached based on a pattern present in numerous observations.numerous observations.

• In inductive reasoning you draw a conclusion In inductive reasoning you draw a conclusion based on specific evidence. The conclusion based on specific evidence. The conclusion may be more or less likely, but it is not may be more or less likely, but it is not necessarily true.necessarily true.

• Most often used in science and law.Most often used in science and law.

Example of Inductive ReasoningExample of Inductive Reasoning

• Between 1850 and 1930, measurements of Between 1850 and 1930, measurements of the population size showed that each time the population size showed that each time the populations of Snowshoe hares the populations of Snowshoe hares increased or decreased the populations of increased or decreased the populations of lynx also increased or decreased.lynx also increased or decreased.

• The conclusions are that the populations of The conclusions are that the populations of Snowshoe hares and lynx depend upon each Snowshoe hares and lynx depend upon each other.other.

Deductive ReasoningDeductive Reasoning

• A form of reasoning in which evidence or A form of reasoning in which evidence or observations are secondary.observations are secondary.

• In deductive reasoning the concern is to In deductive reasoning the concern is to define a commonly accepted VALUE or define a commonly accepted VALUE or BELIEF that prepares the way for the BELIEF that prepares the way for the argument you want to make.argument you want to make.

Deductive ReasoningDeductive Reasoning

• In deductive reasoning the conclusion is In deductive reasoning the conclusion is that something must be true because it is a that something must be true because it is a special case of a general principle that is special case of a general principle that is known to be true.known to be true.

• Based upon two premises and a conclusion (syllogism). Logically, the conclusion is true if the premises are true.

Example of Deductive ReasoningExample of Deductive Reasoning

• Premise one: If Sarah is ten feet tall, she can Premise one: If Sarah is ten feet tall, she can dunk a basketball.dunk a basketball.

• Premise two: Sarah is ten feet tall.Premise two: Sarah is ten feet tall.

• Conclusion: Sarah can dunk a basketball.Conclusion: Sarah can dunk a basketball.

Valid conclusionValid conclusion

Example of Deductive ReasoningExample of Deductive Reasoning

• Premise one: If Sarah is ten feet tall, she can Premise one: If Sarah is ten feet tall, she can dunk a basketball.dunk a basketball.

• Premise two: Sarah can dunk a basketball.Premise two: Sarah can dunk a basketball.

• Conclusion: Sarah is ten feet tall.Conclusion: Sarah is ten feet tall.

Invalid conclusionInvalid conclusion

Example of Deductive ReasoningExample of Deductive Reasoning

• Premise one: If there is fog the plane will be Premise one: If there is fog the plane will be diverted.diverted.

• Premise two: There is no fog.Premise two: There is no fog.

• Conclusion: The plane will not be diverted.Conclusion: The plane will not be diverted.

Valid or invalid conclusion?Valid or invalid conclusion?

EcologyEcology

The study of relationships between organisms The study of relationships between organisms and their environment.and their environment.

EnvironmentEnvironment == biotic and abiotic factors that biotic and abiotic factors that affect an organism during its lifetime.affect an organism during its lifetime.

Abiotic factors:Abiotic factors: nonliving parts of thenonliving parts of the environment - water, minerals, sunlight, climate.

Biotic factors:Biotic factors: organisms that are a part organisms that are a part of the environmentof the environment

Laws of ThermodynamicsLaws of Thermodynamics

First Law (ConservationFirst Law (Conservation of Energy)of Energy)Energy is neither created nor destroyed; it Energy is neither created nor destroyed; it is always conserved.is always conserved.

Second LawSecond LawEnergy always tends to go from a more Energy always tends to go from a more usable form to a less usable form, so the usable form to a less usable form, so the amount of energy available to do work amount of energy available to do work decreases (entropy occurs). decreases (entropy occurs).

Consequence Of Laws Of Consequence Of Laws Of Thermodynamics For Living Thermodynamics For Living

OrganismsOrganisms

Organisms require a constant input of Organisms require a constant input of energy to maintain a high level of energy to maintain a high level of

organization.organization.

Types of Energy SystemsTypes of Energy Systems

PhotosynthesisPhotosynthesis(Transformation of Light Energy)(Transformation of Light Energy)

6 CO6 CO22 + 12 H + 12 H22O + radiant energy O + radiant energy

C6H12O6 + 6 H+ 6 H22O + 6 OO + 6 O22

Stores energy in chemical bondsStores energy in chemical bonds

RespirationRespiration(Transformation of Chemical Energy)(Transformation of Chemical Energy)

CC66HH1212OO66 + 6 H + 6 H22O + 6 OO + 6 O22

6 CO6 CO22 +12 H +12 H22O + energyO + energy

Provides energy for “work”Provides energy for “work”

Ecological Studies Show How the Whole Ecological Studies Show How the Whole System Works.System Works.

Focus:Focus:

1.1. The roles played by members of a The roles played by members of a community community

2. The energy/resource structure of the 2. The energy/resource structure of the system. system.

Ecosystem OrganizationEcosystem Organization

Each system can help clarify different Each system can help clarify different issues.issues.

1. Trophic Pyramids1. Trophic Pyramids

2. Food Webs2. Food Webs

3. Nutrient Cycles3. Nutrient Cycles

(Autotrophs and Heterotrophs)

1.1. The number of The number of trophic levels are trophic levels are limited. At each limited. At each trophic level, there trophic level, there is a dramatic is a dramatic reduction in energy.reduction in energy.

2.2. Eating at lower Eating at lower trophic levels means trophic levels means more resources are more resources are available. available.

Pyramids of Pyramids of Energy Energy Suggests:Suggests:

Pyramids of Energy Suggests:Pyramids of Energy Suggests:

1.1. The number of trophic levels are limited. The number of trophic levels are limited. At each trophic level, there is a dramatic At each trophic level, there is a dramatic reduction in energy.reduction in energy.

2.2. Eating at lower trophic levels means more Eating at lower trophic levels means more resources available. resources available.

3.3. Movement up the pyramid explains the Movement up the pyramid explains the problems of problems of Biological MagnificationBiological Magnification

((DDT, PCBs, etc.) DDT, PCBs, etc.)

Biological MagnificationBiological Magnification

Concentration of a compound can increase at Concentration of a compound can increase at higher trophic levels because higher trophic levels because each individualeach individual in a higher trophic level must eat in a higher trophic level must eat manymany individuals of a lower trophic level to survive. individuals of a lower trophic level to survive.

Although the energy acquired by eating those Although the energy acquired by eating those organisms from a lower trophic level is used, organisms from a lower trophic level is used, the toxic compounds may remain (Especially the toxic compounds may remain (Especially true for compounds that are stored in fats and true for compounds that are stored in fats and are not easily broken down.).are not easily broken down.).

Food websFood webs

Are interlocking Are interlocking food chains food chains based on which based on which organisms eat organisms eat which. which.

Arrows show the Arrows show the direction of direction of food/energy food/energy flowflow

Ecological PyramidsEcological Pyramids

• Pyramid of energyPyramid of energy

• Pyramid of numbersPyramid of numbers

• Pyramid of biomassPyramid of biomass

Gross Primary ProductivityGross Primary Productivity = total = total amount of energy captured by amount of energy captured by photosynthesis for an ecosystem.photosynthesis for an ecosystem.

Keystone SpeciesKeystone Species

Food webs suggest that keystone species may Food webs suggest that keystone species may be important. Changes in one species may be important. Changes in one species may dramatically change the entire ecosystem dramatically change the entire ecosystem through links in the webthrough links in the web. .

Keystone SpeciesKeystone Species = = Species whose presence is Species whose presence is essential to community function and stability essential to community function and stability (e.g., Krill in Antarctica).(e.g., Krill in Antarctica).