Institute for Systems Biology & Bellevue School Institute for Systems Biology & Bellevue School DistrictDistrict

Case StudyCase Study

Your mission is to use your knowledge Your mission is to use your knowledge of networks and life (extreme and of networks and life (extreme and non-extreme) to:non-extreme) to:– Analyze how an ecological Analyze how an ecological

disturbance could affect an entire disturbance could affect an entire ecosystem.ecosystem.

– Analyze the effect of natural events Analyze the effect of natural events and human activities on the Earth’s and human activities on the Earth’s capacity to sustain biological capacity to sustain biological diversity.diversity.

Case Study DetailsCase Study Details

Setting:Setting: A large body of water A large body of water Time:Time: 1952 1952 Event:Event: A causeway is built across the A causeway is built across the

body of water separating the north body of water separating the north end from the south end. No water is end from the south end. No water is exchanged between the two sides. exchanged between the two sides.

The general questionThe general question: What effect : What effect does this have on the ecosystem?does this have on the ecosystem?

The SpecificsThe Specifics

In 1902, a railroad built a In 1902, a railroad built a train trestle that went directly train trestle that went directly across the body of water. In across the body of water. In the 1950’s, a causeway the 1950’s, a causeway replaced the trestle allowing replaced the trestle allowing for safer and faster travel of for safer and faster travel of the trains. the trains.

The causeway is a solid, The causeway is a solid, raised roadway made of 50 raised roadway made of 50 million cubic yards of rock, million cubic yards of rock, sand and gravel. However, sand and gravel. However, unlike the trestle, the unlike the trestle, the causeway does not allow causeway does not allow circulation of water between circulation of water between the two sides. This basically the two sides. This basically split the lake into two halves, split the lake into two halves, the North arm and the South the North arm and the South arm.arm.

The causeway separating The causeway separating the North and South armsthe North and South arms

This body of water is a dynamic This body of water is a dynamic ecosystem and is affected by the amount ecosystem and is affected by the amount

of rainfall receivedof rainfall received1984 2004

BrainstormingBrainstorming

What differences do you notice, if What differences do you notice, if any, between the north and the any, between the north and the south arms?south arms?

Why could building a causeway Why could building a causeway cause the water to be two different cause the water to be two different colors?colors?– What might be some causes of the What might be some causes of the

change seen?change seen?

New InformationNew Information

Only one arm of this body of water Only one arm of this body of water receives freshwater on a continuous basis.receives freshwater on a continuous basis.– How could this be?How could this be?– Does this lead to further explanations or does Does this lead to further explanations or does

this narrow down your possible explanations?this narrow down your possible explanations? If only one arm is receiving freshwater, If only one arm is receiving freshwater,

what type of ecosystem must this be?what type of ecosystem must this be?– Hint: What different types of water ecosystems Hint: What different types of water ecosystems

are found on Earth?are found on Earth? Why does the amount of rainfall received Why does the amount of rainfall received

further affect this ecosystem?further affect this ecosystem?

No Salt Low Salt High Salt

No Salt Low Salt High Salt

The Great Salt Lake The Great Salt Lake EcosystemEcosystem

BrainstormingBrainstorming

What organisms are part of the ecosystem in What organisms are part of the ecosystem in the Great Salt Lake?the Great Salt Lake?

What differences do you notice, if any, What differences do you notice, if any, between the north and the south arm of the between the north and the south arm of the lake?lake?

Which half of the lake receives fresh water? Which half of the lake receives fresh water? How do you think this affects the lake?How do you think this affects the lake?

Why do you think the Great Salt Lake is a Why do you think the Great Salt Lake is a different color in the North end of the Lake?different color in the North end of the Lake?

HypothesizingHypothesizing

What factors may affect the growth What factors may affect the growth of of HalobacteriumHalobacterium??

How could you design an experiment How could you design an experiment that could test your hypotheses? that could test your hypotheses?

OptimizeOptimize

The decision strategy of choosing the The decision strategy of choosing the alternative that gives the best or alternative that gives the best or optimal overall value.optimal overall value.

To increase the efficiency or To increase the efficiency or effectiveness of a process as much effectiveness of a process as much as possible.as possible.