Solution Manual for Biology Laboratory Manual, 11th Edition
Solution Manual for Biology Laboratory Manual, 11th Edition gives you the clarity you need to excel in your studies.
Michael Davis
Contributor
5.0
51
4 months ago
Preview (16 of 595)
Sign in to access the full document!
INVESTIGATIONS IN BIOLOGY
The best way to learn biology is to do biology. There are many ways to do this. For example,
throughout this manual you’ll find directed labs that use traditional skills and activities (e.g.,
how to use a microscope) to immerse you in the process of biology. Similarly, thematic labs will
involve you in discovering the themes of biology (e.g., evolution, ecology). These activities will
help you experience the biology you have learned from lectures, your textbook, and this manual.
We also want you to design your own experiments so that you can learn biology your way. These
activities, which are part of every lab, are investigative labs. Some of these investigations are
independent activities, whereas others are extensions of topics studied in directed labs and
thematic labs. In investigative labs, you’ll apply the skills you’ve learned to answer your own
questions about biology. In doing so, you’ll be challenged to create and develop your way of
answering scientific questions. Investigations in biology often go far beyond simply following
the steps of the scientific method. Indeed, investigation is a broad pursuit that includes
observations, experiments, analysis of the work of others, reliable procedures, and repetition.
It’s more of an approach to answering questions than it is a set of rigid procedures. Although
investigation doesn’t have to be complicated, it does require creativity, planning, patience, and
attention to detail. Investigations proceed along a variety of paths, depending on the investigator
and the question being asked. But the steps we’ve described below can improve any
investigation, including those suggested in this lab manual.
Establish a clear question. Investigations begin with observations and questions. Simple,
straightforward questions are usually the best. When you’ve decided on your question, write it
down. You will be surprised how much easier it is to recall and refine a written question than it is
to develop a vague idea rattling around in your head. Make sure your question is stated clearly.
And here's a tip for asking productive questions: Learn as much as you can about what you’re
proposing to do. The more background information you have, the better your questions will be,
and the more likely your results will make sense. Not all questions require controlled
experiments. For example, some investigations are descriptive rather than experimental. Decide
whether your question is best answered with experiments in controlled systems or with
observations in natural systems. You may investigate the impact of pollutants by administering
them to controlled organisms, or you may choose to describe observations about a pollutant’s
effects in a natural community. Both approaches can lead to interesting and important results.
Design a reliable experiment. Outline what you are going to do, and write down the steps of
your procedure in numerical order. The most reliable experiments are usually the simplest ones.
Complicated procedures are often hard to repeat and are prone to error. Remember that a
hallmark of good science is that it’s repeatable. To keep things simple and repeatable it’s best—
whenever you can—to isolate a single variable and hold all other conditions constant. That way
you can easily repeat your experiment and refine your ability to reliably measure the most
important variable. Simple, reliable procedures also make it easier to establish appropriate
controls. If all conditions surrounding your experiment except one variable are held constant,
then it is relatively easy to design a good control. A good control is a replicate procedure with
the variable of interest either held constant or absent. For example, if you want to detect the
effects of a pollutant on plant growth, then you need a control with the same growth conditions
as the pollutant treatments, but without the pollutant you are studying. Another good tip for
The best way to learn biology is to do biology. There are many ways to do this. For example,
throughout this manual you’ll find directed labs that use traditional skills and activities (e.g.,
how to use a microscope) to immerse you in the process of biology. Similarly, thematic labs will
involve you in discovering the themes of biology (e.g., evolution, ecology). These activities will
help you experience the biology you have learned from lectures, your textbook, and this manual.
We also want you to design your own experiments so that you can learn biology your way. These
activities, which are part of every lab, are investigative labs. Some of these investigations are
independent activities, whereas others are extensions of topics studied in directed labs and
thematic labs. In investigative labs, you’ll apply the skills you’ve learned to answer your own
questions about biology. In doing so, you’ll be challenged to create and develop your way of
answering scientific questions. Investigations in biology often go far beyond simply following
the steps of the scientific method. Indeed, investigation is a broad pursuit that includes
observations, experiments, analysis of the work of others, reliable procedures, and repetition.
It’s more of an approach to answering questions than it is a set of rigid procedures. Although
investigation doesn’t have to be complicated, it does require creativity, planning, patience, and
attention to detail. Investigations proceed along a variety of paths, depending on the investigator
and the question being asked. But the steps we’ve described below can improve any
investigation, including those suggested in this lab manual.
Establish a clear question. Investigations begin with observations and questions. Simple,
straightforward questions are usually the best. When you’ve decided on your question, write it
down. You will be surprised how much easier it is to recall and refine a written question than it is
to develop a vague idea rattling around in your head. Make sure your question is stated clearly.
And here's a tip for asking productive questions: Learn as much as you can about what you’re
proposing to do. The more background information you have, the better your questions will be,
and the more likely your results will make sense. Not all questions require controlled
experiments. For example, some investigations are descriptive rather than experimental. Decide
whether your question is best answered with experiments in controlled systems or with
observations in natural systems. You may investigate the impact of pollutants by administering
them to controlled organisms, or you may choose to describe observations about a pollutant’s
effects in a natural community. Both approaches can lead to interesting and important results.
Design a reliable experiment. Outline what you are going to do, and write down the steps of
your procedure in numerical order. The most reliable experiments are usually the simplest ones.
Complicated procedures are often hard to repeat and are prone to error. Remember that a
hallmark of good science is that it’s repeatable. To keep things simple and repeatable it’s best—
whenever you can—to isolate a single variable and hold all other conditions constant. That way
you can easily repeat your experiment and refine your ability to reliably measure the most
important variable. Simple, reliable procedures also make it easier to establish appropriate
controls. If all conditions surrounding your experiment except one variable are held constant,
then it is relatively easy to design a good control. A good control is a replicate procedure with
the variable of interest either held constant or absent. For example, if you want to detect the
effects of a pollutant on plant growth, then you need a control with the same growth conditions
as the pollutant treatments, but without the pollutant you are studying. Another good tip for
designing successful investigations is to use readily available organisms and materials for
procedures. Good science does not have to be complicated with expensive equipment or exotic
organisms. There is no need to use a rat if a fruit fly will do. If the experiment you’re proposing
requires materials other than the ones provided, ask your instructor if those materials are
available. Also, get input from other people about your proposed work—investing time before
you do the work can save much time later.
Work objectively. Decide beforehand what result will validate your hypothesis and answer your
question, and what result will invalidate your hypothesis. If possible, use tables and graphs to
show your results. Write down not just your data, but also what your data mean. Try not to think
about what your results should be. Instead, accept what they are. Some of the most interesting
results are those that we didn’t predict, for unexpected results often lead to more questions. And
that’s a good thing!
Strengthen your conclusions. The best way to strengthen your conclusions is to repeat your
work. Along with repetition, conclusions are stronger when they are supported by different kinds
of evidence. For example, if you are investigating the effects of a nutrient on plant growth, then
your conclusion is stronger if you investigated more than one species of plant. Similarly,
conclusions based on highly controlled laboratory experiments are strengthened by corroborative
data on plant growth in natural communities with various levels of that nutrient.
Be prepared to revise your questions and experimental design. You’d be surprised how many
initial experiments in an investigation “don’t work.” The results make no sense, or you can’t
measure the variable you thought you were going to measure with the precision you expected.
Or, the first experiment gives one result and the second experiment gives another. If this
happens, do not be overly concerned—this is precisely how “real science” goes. Think about
what might be the problem; perhaps it’s arising from some source of variation in one replicate
that’s not in the other replicates. The cure for that problem is revision and repetition. It’s worth
saying again … good science is reliable and repeatable.
Figure out what your data mean. Discuss your data in light of your original question or
hypothesis. Do your results support or falsify your hypothesis? Use your data to explain your
reasoning. What is the significance of your work? That is, what can you conclude from your
investigation? Are there other interpretations from results? How do your results compare with
those of others? Based on what you’ve learned, can you now ask different or more probing
questions to learn even more? Remember that correlation does not necessarily indicate cause and
effect. If you had problems with your investigation, discuss how these problems might have been
avoided. If you could repeat or revise your work, what would you do differently?
Be prepared to report your work. Scientists often remark that “you haven’t done science until
you have published your work.” Lab write-ups are the beginning of a publication.
procedures. Good science does not have to be complicated with expensive equipment or exotic
organisms. There is no need to use a rat if a fruit fly will do. If the experiment you’re proposing
requires materials other than the ones provided, ask your instructor if those materials are
available. Also, get input from other people about your proposed work—investing time before
you do the work can save much time later.
Work objectively. Decide beforehand what result will validate your hypothesis and answer your
question, and what result will invalidate your hypothesis. If possible, use tables and graphs to
show your results. Write down not just your data, but also what your data mean. Try not to think
about what your results should be. Instead, accept what they are. Some of the most interesting
results are those that we didn’t predict, for unexpected results often lead to more questions. And
that’s a good thing!
Strengthen your conclusions. The best way to strengthen your conclusions is to repeat your
work. Along with repetition, conclusions are stronger when they are supported by different kinds
of evidence. For example, if you are investigating the effects of a nutrient on plant growth, then
your conclusion is stronger if you investigated more than one species of plant. Similarly,
conclusions based on highly controlled laboratory experiments are strengthened by corroborative
data on plant growth in natural communities with various levels of that nutrient.
Be prepared to revise your questions and experimental design. You’d be surprised how many
initial experiments in an investigation “don’t work.” The results make no sense, or you can’t
measure the variable you thought you were going to measure with the precision you expected.
Or, the first experiment gives one result and the second experiment gives another. If this
happens, do not be overly concerned—this is precisely how “real science” goes. Think about
what might be the problem; perhaps it’s arising from some source of variation in one replicate
that’s not in the other replicates. The cure for that problem is revision and repetition. It’s worth
saying again … good science is reliable and repeatable.
Figure out what your data mean. Discuss your data in light of your original question or
hypothesis. Do your results support or falsify your hypothesis? Use your data to explain your
reasoning. What is the significance of your work? That is, what can you conclude from your
investigation? Are there other interpretations from results? How do your results compare with
those of others? Based on what you’ve learned, can you now ask different or more probing
questions to learn even more? Remember that correlation does not necessarily indicate cause and
effect. If you had problems with your investigation, discuss how these problems might have been
avoided. If you could repeat or revise your work, what would you do differently?
Be prepared to report your work. Scientists often remark that “you haven’t done science until
you have published your work.” Lab write-ups are the beginning of a publication.
Loading page 6...
Loading page 7...
Loading page 8...
Loading page 9...
Loading page 10...
Loading page 11...
Loading page 12...
Loading page 13...
Loading page 14...
Loading page 15...
Loading page 16...
13 more pages available. Scroll down to load them.
Preview Mode
Sign in to access the full document!
100%