You are earning your Ph.D. in marine biology, studying the microbial ocean community. This year, you are shocked to discover that one of your study sites has become contaminated due to an industrial waste water pipe. This dumping is drastically raising the temperature and lowering the salinity of the water. What do you expect to find in your survey of the ecosystem, and what might you find in a survey years from now?

Question

A.  Most species will be wiped out this year, and in subsequent years even fewer will remain.
B.  The individuals will turn on genes to adapt to these changes, and the populations will end up largely the same this year and following years.
C.  Many species will have decreased or disappeared from this site, but later some species may increase in population if they acquire adaptive mutations. Also you may see some new species expand into the site.
D.  Most species will be wiped out this year, and it will take millions of years for new species to evolve -- until then the site will be devoid of life.


Clarify question:
What is the key concept addressed by the question?

What type of thinking is required?


Gather Content:
What do you already know about how an ecosystem reacts to pollution? What other information is related to the question? 


Choose Answer:
Given what you now know, what information is most likely to produce the correct answer?


Reflection on Process:
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

C.  Many species will have decreased or disappeared from this site, but later some species may increase in population if they acquire adaptive mutations. Also you may see some new species expand into the site.


Clarify question:
What is the key concept addressed by the question?
The key concepts is predicting how an environment will be affected by pollution.

What type of thinking is required?
This is an analyze level question, you will need to break down the question into its components to get to the answer.


Gather Content:
What do you already know about how an ecosystem reacts to pollution? What other information is related to the question? 
The environment has experienced a drastic change. Initially most species will not be adapted to this different environment, but if the change is persistent over a long span of time what will happen? There will be a new set of selection pressures on the community.


Choose Answer:
Given what you now know, what information is most likely to produce the correct answer?
After an initial decrease in the population, some species will adapt. Also some species may be better suited to live in the new set of conditions. Some species may have been held to low levels because of ecological interaction with other species, but with those competing species gone their population may begin to expand. Also there may be new species that can now live in the newly modified environment.


Reflection on Process:
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Were you able to make the correct choice? Changes to an environment are often initially detrimental but given the short generations of microbial species, they can quickly respond to new sets of selection pressures.