SF Bay Estuary Ecology SF Bay Estuary Ecology NotesNotes

A. Definitions:

1. Ecology- The study of the interactions of organisms

with one another and their environment.

2. Ecosystem-a self-sustaining collection of organisms and their environment.

3. Estuary-a partially enclosed body of water where

fresh river water mixes with salty ocean water.

I. What is Ecology?

A. A=Abiotic Factors (non-living)

1. Factors in SF Bay include:

• Temperature• Water• Sunlight • Wind • Salinity:

- varies from 0ppt to 35ppt depending on the location in the estuary.

• Rocks and soil• Catastrophes: fires, floods, earthquakes

II. The ABC’s of Ecology

B. B=Biotic Factors (living)

1. Factors in SF Bay include:• Plants, Animals, Protists, Fungi, Bacteria

2. Organisms are classified as follows into trophic levels (“feeding” levels):• Producers- organisms that make their own food from

inorganic substances

• Consumers-organisms that receive their energy from

consuming other organismsherbivores-eat plantscarnivores-eat herbivores and each other omnivores-eat both plants and animals

• Decomposers -organisms that obtain their energy from non-living organic matter

C. C=Cultural Factors (human impact)

1. Factors in SF Bay include:

• Endangered plants and animals- 30 species of endangered plants and animals use the

Estuary during at least a part of their lives.

• Diversion of Fresh Water- ~50% annual flow of fresh water is diverted for agriculture.

• Waste and Run-Off- Almost 200 industry sites dump wastes into the Estuary

each year-including 300 tons of trace metals. Urban runoff contributes even more pollutants.

• Destruction of Tidal Marshes- 97% of the tidal marshes have been destroyed or altered.

A. The Sun is the Source of Energy

1. Producers convert the sun’s energy into chemical energy through a process called photosynthesis.

2. Equation:

Carbon Dioxide + Water = Glucose + Oxygen

6CO2 + 6H20 = C6H12O6 + 6O2

III. Energy in the Ecosystem

B. Food Chains and Food Webs1. Consumers receive energy by eating producers or other consumers.

2. A food chain is a diagram showing the flow of energy through individual organisms.

3. Example:

III. Energy in the Ecosystem

diatoms shrimp fish sea lion

Source Producers 1º Consumers2º Consumers Top consumers

Trophic level

B. Food Chains and Food Webs

4. A food web is a diagram illustrating the flow of energy through an entire ecosystem.

5. Example:

III. Energy in the Ecosystem

*Arrows show direction of energy flow

Figure 47-21

C. Ecological Pyramids -An ecological pyramid represents energy relationships among trophic levels.

1. Pyramid of Energy

III. Energy in the Ecosystem

10% rule: •Only 10% of energy can be transferred to the next energy level!•90% of energy is used by organism or lost as heat

Figure 47-16

More EnergyMore Organisms

Less EnergyFewer Organisms

C. Ecological Pyramids

2. Pyramid of Biomass and Numbers

III. Energy in the Ecosystem

Figure 47-16

1. Suggest an explanation why there are fewer lions than zebras on the African plains.

IV. Questions to Consider

*90% of energy is lost at each level so there isn’t as much energy available for top consumers. Also, it is easier to get food as a producer so population numbers are higher.

2. More agricultural land would be available to provide food for the growing human population if humans did not eat meat. Explain why. A person gets the same amount of

energy from eating the same amount of either meat (cow) or grain. But due to the 10% rule, much more grain will be used if the person eats the cow for energy. Making more grain uses land and resources that could be available to feed more people. MORE-->

Grain100

energy

Cow10

energy

or

Grain10

energy

Person1

energy

3. Are there other implications to the fact that only 10% of energy is passed to the next trophic level?

IV. Questions to Consider

YES. Though 90% of energy is lost as heat, toxic chemicals are not lost and they accumulate in living tissue. This means the effect of pollution is much greater for top level consumers. This process is called BIOACCUMULATION.

Grain100

energy 100

pesticide

Cow10 energy 100 pesticide

or

Grain10

energy 10

pesticide

Person1 energy

10 or 100 pesticide

For example, if each unit of grain is polluted with 1 unit of pesticide, the person who eats the grain directly gets only 10 units of pesticide. The person who eats the cow gets 100 units!

V. Summary Reading questions

4. Summary: p. 1931. LIGHT (PHOTOSYNTHESIS), CHEMICAL BONDS

(CHEMOSYNTHESIS)2. ENERGY FLOW: PRODUCERS CONSUMERS3. 10% OF ENERGY IS TRANSFERRED FROM ONE TROPHIC

LEVEL TO THE NEXT.4. RELATIONSHIP: AUTOTROPH (PRODUCER) EATEN BY

HERBIVORE. OMNIVORE EATS BOTH.5.5TH CONSUMER 0.001%4TH CONSUMER 0.01%3RD CONSUMER 0.1%2ND CONSUMER 1%1ST CONSUMER 10%PRODUCER 100%

V. Other Reading Info

1. SourceIntegrated Science, p. 183-1932. Vocabulary:ecologybiospherespeciespopulationscommunitiesecosystembiomeautotrophsproducersphotosynthesischemosynthesisheterotrophsWith definitions! If any of these not listed, please add the word.3. OutlineI. Interactions and Interdependence: EcologyII. Levels of OrganizationIII. Ecological MethodsIV. Producers, Consumers V. Feeding RelationshipsVI. Ecological PyramidsDoes not have to be in this exact format, but should have further information!

consumersherbivorescarnivoresomnivoresdetritivoresdecomposersfood chainfood webtrophic levelecological pyrimidbiomass

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are needed to see this picture.

VI. SF Bay Scorecard Scores from 0 - 100Source: The Bay Institute (bay.org, 2005)