Slide 1 / 12 1 Bacteria play central biological roles including - - PDF document

1 Bacteria play central biological roles including producers, parasites, mutualistic symbionts, and decomposers.

• a. Select three of the ecological roles above. For each one, describe

how bacteria carry out the role and discuss its ecological importance.

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• b. Explain how bacteria can be altered to make genetically

engineered products.

Bacteria play central biological roles including producers, parasites, mutualistic symbionts, and decomposers.

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2 Starting with a bare sand beach, discuss the natural succession from a pioneer species to a climax community with respect to:

• a. Abiotic factors

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• b. Biotic factors

Starting with a bare sand beach, discuss the natural succession from a pioneer species to a climax community with respect to:

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• c. The likely order of the stages of succession

Starting with a bare sand beach, discuss the natural succession from a pioneer species to a climax community with respect to:

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3 Living organisms play an important role in the recycling of many elements within an ecosystem.

• a. Discuss how various types of organisms and their biochemical reactions

contribute to the recycling of either carbon or nitrogen in an ecosystem. Include in your answer one way in which human activity has an impact on the nutrient cycle you have chosen.

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4 Compared with other terrestrial biomes, deserts have extremely low productivity.

• a. Discuss three abiotic factors that limit productivity in deserts.

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• b. Describe a four-organism food chain that might characterize a desert

community, and identify the trophic level of each organism.

Compared with other terrestrial biomes, deserts have extremely low productivity.

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5 In recent years, the fish population in a lake has been

• decreasing. This is due, in part, to events known as “fish kills,” a

large die-off of fish. Fish kills occur when oxygen-consuming processes in the aquatic ecosystem require more oxygen than the plants in the ecosystem produce, thereby reducing the amount of dissolved oxygen available to the fish. One proposed explanation for the increased fish kills in recent years is that human activities have caused sediment to runoff into the lake.

• a. Identify one biotic factor you would expect to see in the lake as a result
• f increased sediment containing fertilizers.

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In recent years, the fish population in a lake has been

• decreasing. This is due, in part, to events known as “fish kills,” a

large die-off of fish. Fish kills occur when oxygen-consuming processes in the aquatic ecosystem require more oxygen than the plants in the ecosystem produce, thereby reducing the amount of dissolved oxygen available to the fish. One proposed explanation for the increased fish kills in recent years is that human activities have caused sediment to runoff into the lake.

• b. Explain how algal growth could affect the amount of sunlight received

by other organisms in the lake.

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In recent years, the fish population in a lake has been

• decreasing. This is due, in part, to events known as “fish kills,” a

large die-off of fish. Fish kills occur when oxygen-consuming processes in the aquatic ecosystem require more oxygen than the plants in the ecosystem produce, thereby reducing the amount of dissolved oxygen available to the fish. One proposed explanation for the increased fish kills in recent years is that human activities have caused sediment to runoff into the lake.

• c. When algae die, the populations of decomposers increase rapidly, as

they have an abundant food supply. Identify the process carried out by these organisms that uses oxygen and contributes to fish kills.

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In recent years, the fish population in a lake has been

• decreasing. This is due, in part, to events known as “fish kills,” a

large die-off of fish. Fish kills occur when oxygen-consuming processes in the aquatic ecosystem require more oxygen than the plants in the ecosystem produce, thereby reducing the amount of dissolved oxygen available to the fish. One proposed explanation for the increased fish kills in recent years is that human activities have caused sediment to runoff into the lake.

• d. How can humans prevent this ecological damage?

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