Biology 1110 Lab

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Biology - 1110 Lab
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• Your Instructor Colleen Roden
• A few things about me
• Undergraduate work done at TTU
• Working on M.S. in Microbiology
• Working towards Ph.D. in Immunology, emphasizing
  in research
• Previously taught overseas.

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The 1110 Lab

• Designed for Science Majors!!
• The lab counts as 1/4 the course grade
• Lab syllabus guidelines to the lab each week

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• Safety First!!
• Do not eat, drink, smoke, or apply cosmetics
  when in the lab.
• Use the equipment properly. If you have any
  questions or problems, contact your instructor.
• Clean up spills immediately.
• Report all injuries--no matter how
  minor--immediately to your instructor.
• If you have long hair, tie it back. If you use
  open flames, roll up loose or long sleeves.

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• Lab Safety continued
• Never taste any substance or solution. Do not put
  anything in the lab into your mouth.
• Treat all live animals gently and with respect.
• At the end of the lab, wash your hands thoroughly
  and return all equipment and supplies to their
  original locations.
• Lab safety is on W-2 in your lab manual.

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Advice for a SUCCESSFUL Lab

• Read each lab BEFORE coming to class !
• Get to the lab ON TIME! ( I will not wait for
  you!)
• Take notes during lab (both lecture and
  application).
• Pay attention! (Its your grade on the line.)
• Ask questions! (Im not a mind reader.)
• Take your time. (This isnt a race and you will
  be tested on most material covered.)

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Missing a Lab

• Automatically fails younot really.
• If you have to miss a lab due to sickness, death
  in the family, etc. please let me know as soon as
  possible.
• It will be your responsibility to get notes from
  another student or copies of handouts that were
  given during the missed lab.
• More than two absences will be noted with your
  lecture instructor.

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Todays Lab

• Turn to Exercise 1 on 1-1 Measurements
• Turn to Understanding the Nature of Science
  (right after W-2).
• You may take notes if you wish because you will
  see this material again either on quizzes or your
  first lab exam or BOTH!

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Scientific MethodSteps

• Ask a question.
• Formulate a hypothesis (educated guess).
• Two types of hypotheses
• Null (Ho) the tested hypothesis no
  change
• Alternative (Ha) tentatively accepted
  if there is a change

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The Scientific Method continued

• Formulate testable predictions How can we test
  our hypothesis?
• Conduct tests of our predictions may include
  observations/experiments.
• Analyze the results Do they defend your null
  hypothesis? Do you need to do another test?

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Todays Application

• Question
• What is the ratio of male to female births in
  human populations?
• Null (Ho)
• Human populations exhibit a 11 sex ratio at
  birth. (The probability of being born male is
  equal to the probability of being born female.)
• Pm Pf 0.5 or 50 chance of either (X, Y
  chromosomes)
• Alternative (Ha)
• Human populations do not exhibit a 11 sex ratio
  at birth.

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Testable Predictions

• What would be a testable prediction from our Null
  hypothesis?
• A random sample at birth from a human population
  should exhibit a 11 sex ratio.

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Testing Our Predictions

• How could we come up with a ratio without leaving
  the lab to count human populations?
• Count the males and females in our lab!
• Is this a good test? Why or why not?
• This is not good because it is NOT random!
• What would be a better test?
• Count the males and females (living and dead) of
  your generation in your immediate family
  (brothers and sisters) and total those numbers
  for your lab bench. Then calculate the ratio.

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Testing continued

• Is this a better test? Why or why not?
• It is better because it is more random.
• What would be the best test for our situation?
• Collect all the data from each lab bench for the
  entire lab and calculate the ratio.
• Why is this an even better test than before?
• It is better because it is more random and gives
  us more numbers to work with.

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Analyzing Our Results

• What is our ratio?
• _____ males _____ females
• Is it exactly 11?
• Probably not. This does not mean that our null
  hypothesis is false. We must consider sampling
  error.
• Sampling error the difference between our
  sample sex ratio and the entire populations sex
  ratio. Is our difference too much?

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Calculating Sampling Error and Statistics

• Statistics used to determine if differences
  between the actual results and those predicted
  from the Null Hypothesis are due to sampling
  error or due to a false Null Hypothesis.
• Example The Quarter Flip (page 4 in
  Understanding the Nature of Science)
• Chi-Square Goodness of Fit Test used for
  probabilities of specific outcomes and
  categorical data (heads/tails, male/female)

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Chi Square Equation
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Chi-Square Goodness of Fit Test

• Page 6 in Understanding the Nature of Science for
  format of Chi-Square.
• Use Chi-Square table for for critical values.
  (degrees of freedom categories 1)
• Using the Chi-Square format, analyze your results
  from the human sex ratio.
• If your Chi-Square results are less than the
  critical value from the table, you will accept
  your Null hypothesis.
• If your Chi-Square results are more than the
  critical value from the table, you will reject
  your Null hypothesis.

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Publishing Your Results

• Before the answer to the question can be accepted
  as scientific it must be published in Primary
  Literature.
• Primary literature original articles describing
  research projects written by the researchers and
  published in peer-reviewed journals.
• These articles follow the format Abstract,
  Introduction, Methods, Results, Discussion,
  Literature Cited

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Primary Literature

• Look at Appendix II-1 (after p. 546) for a
  detailed description of format.
• Books and review articles (summaries of many
  articles on a topic) are NOT considered primary
  literature. Neither are articles in Time,
  National Geographic, Discover, Seventeen, etc.
• Review the rules of how an article is published
  on page 7 in Understanding the Nature of Science.

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Searching the Primary Literature

• Use the MTSU library.
• Use the MTSU library website.
• Connecting to the library website
• 1. Go to www.mtsu.edu/
• 2. Click on the LIBRARIES link on the left.
• 3. Click on the James E. Walker Library link.
• 4. Click on RESEARCH GATEWAY.
• 5. Click on InfoTrac OneFile.
• 6. Click on Expanded Academic ASAP.

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• If you are on-campus, the computer will
  automatically take you to the search page.
• If you are off-campus, you will be required to
  enter your MTSU e-mail username and password.
• Once on the Expanded Academic index search page,
  you can enter your search terms and criteria.
• Click on Search and see what you get!

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Your Lab Assignment

• You are to find 10 primary literature articles on
  one of those topics (or one of your own that your
  instructor has approved).
• Bring a photocopy of the first page of each
  article with you.
• You may print abstracts off the internet for no
  more than 5 of your articles.