Retake Objective 5: Stability, change, and biodiversity.

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This is a two part question: Which ecosystem has more biodiversity? Explain how you know!

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Which of the following provides evidence to support the claim: If all the phytoplankton were killed in both ecosystems, ecosystem A would remain more stable.

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Which of the following statements would be included in a reasoning that supports the claim: This ecosystem would not remain stable if the wolves were removed. SELECT 1 ANSWER!

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This is a two part question. In the ecosystem pictured, which of the following would result in the LARGEST decrease in BIODIVERSITY? Explain your reasoning in GREAT detail!
A. A virus wiping out the seaweed population.
B. A bacteria infesting all the crabs.
C. A fisherman killing 10 fish in one day.
D. A Dead Zone as described in question 7

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Which graph below represents the response of the rainbow trout population to a ban on fishing? Note: The star in each graph marks the start of the fishing ban. You may add a comment to defend your answer, but you don't have to---sometimes you can select the wrong answer but defend it well enough that I can mark it correct.

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Students looked at the evidence below, they made a claim to answer the question: Which factor below is the main factor leading to the decreasing clarity in Lake Tahoe? They then wrote a reasoning to support their claim. Which students' answer is BEST?

Secchi disk data showing the clarity in Lake Tahoe over time.

Graph showing the clarity of Lake Tahoe in relationship to the Mysis Shrimp presence. The first caption is from 2011.

This graph shows the nitrogen concentration in Lake Tahoe from runoff, over time.

This graph shows the phosphorous concentration in Lake Tahoe from runoff, over time.

Sediment:

Suzi: Nitrogen runoff is the main cause of the decreasing clarity in Lake Tahoe. Overtime, the clarity in Lake Tahoe decreases as the secchi disk can be seen less and less deep down each year. Overtime, nitrogen runoff increases as the amount of nitrogen in the Lake recently reached a high of 20 micrograms per liter. Clearly, nitrogen levels are the largest factor responsible for the lack of clarity in Lake Tahoe. 

Kelly: Mysis Shrimp are the main cause of the decreasing clarity in Lake Tahoe. Overtime, the clarity in Lake Tahoe decreases as the secchi disk can be seen less and less deep down each year. Mysis Shrimp populations have risen in population size each year since their introduction in the 1960's just as clarity has decreased in that time. It is clear this is the factor responsible for the lack of clarity in Lake Tahoe because unlike the other factors, shortly after 2011 when the Mysis shrimp disappeared, the Lake clarity increased in 2014. Then when the shrimp were back, the Lake Clarity decreased again. This factor shows a stronger correlation, than all the others, with the clarity data.  

Tom: Phosphorous runoff is the main cause of the decreasing clarity in Lake Tahoe. Overtime, the clarity in Lake Tahoe increases as the secchi disk can be seen less and less deep down each year. Overtime, phosphorous runoff decreases as the amount of phosphorous in the Lake recently reached a low of 1.5 micrograms per liter. Clearly, nitrogen levels are the largest factor responsible for the lack clarity in Lake Tahoe.

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This is a two part question: Which ecosystem has more biodiversity? Explain how you know!

Which of the following provides evidence to support the claim: If all the phytoplankton were killed in both ecosystems, ecosystem A would remain more stable.

Which of the following statements would be included in a reasoning that supports the claim: This ecosystem would not remain stable if the wolves were removed. SELECT 1 ANSWER!

What evidence could BEST be used to support the claim: Dead zones decrease biodiversity in ecosystems as stability is not able to be maintained.