Biology Notes

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Warmup

• Have your homework out on your desk.
• Do in the back of your comp book (if you have
  one) or on a separate sheet of paper.
• What is science?

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Homework

• Concept map for section 1.1 and 1.3 (a, b, and c)
  on the Learning Targets worksheet

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warmup

• Get out your homeowrk
• Compare your concept map to your partners
  concept map

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Scientific Investigations
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The Scientific Process Outline(copy the
following but leave about a ¼ page between each
section)

• I. What is Science?
• A. Background
• B. Goal of Science
• II. Scientific Design
• A. Scientific Process
• B. Hypotheses Theories
• III. Scientific Method in Action
• Examples and Explanations

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A. Background

• Aristotle- ancient Greek philosopher (384 BCE-322
  BCE or BC)- influenced science in the Western
  world
• Science in ancient times focused on thought only
• True experimentation did not come about until

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A. Background

• Galileo Galilei- the father of modern science
  (Einstein)
• Experiments with a focus on quantitative data

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B. Goal of Science

• Organized way to investigate and understand the
  natural world
• To seek the truth in an objective and
  evidence-based manner
• Scientia (Latin) - knowledge or to know

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II. Scientific Design A. Scientific Process

• An organized process scientists use which depends
  on
• proposing a TESTABLE hypothesis
• Designing a CONTROLLED experiment which can be
  repeated
• Gathering OBSERVABLE, EMPIRICAL, and MEASURABLE
  data
• Composing an evidence-based conclusion after the
  analysis of that data
• No ONE way to do the scientific method
• Reduce bias on the part of the scientist

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A. Scientific Process Steps

• QUESTION/PROBLEM- based on observations
• HYPOTHESIS- statement about the relationship b/w
  2 things
• TESTING- controlled experiment or observations.
• RESULTS- analyze your Q/Q data
• CONCLUSION- confirm/reject your hypothesis draw
  up significance of your results
• Report findings to others so they can repeat the
  experiment.

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B. Theories and Laws

• What is the difference?
• HYPOTHESIS
• Educated guess, based on observations, testable
• Limited statement regarding cause and effect in a
  specific situation
• My car does not start because the battery is
  low
• THEORY
• Enough evidence to accept a group of hypotheses-
  accept to be true based on evidence to date.
• Can be shown to be false if evidence disputes
• Explains WHY something occurs

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Observation vs. Inference

• Observation
• Data we can take in through our senses.
• Very important to all steps of the scientific
  method
• Important that one take good observations and
  measurements
• Inference
• What we can figure out from that data.

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Observation
Ohh This liquid is green and it is leaking from
a brown can. I also smell it.
Observation when studying something describe
only facts that you can see, touch, smell and
hear. You are not making any guesses. THIS
IS NOT AN OPINION!!

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Inference
Based on my observations, I think that this can
is old and is leaking a toxic substance.
Inference using your observations to make a
guess about an object or an outcome THIS CAN BE A
SCIENTIFIC OPINION

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Group Practice

• Give 2 observation on the following
• Give 2 inferences on the following

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Make observation
Scientific Method
Ask question
Develop hypothesis
Test hypothesis with an experiment
Test hypothesis with further experiments
Revise hypothesis
Analyze data and draw conclusions
Hypothesis IS supported
Hypothesis is NOT supported
Develop theory
Wysession, Frank, Yancopoulos, Physical Science
Concepts in Action, 2004, page 8
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What did you notice about the hypothesis?
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About hypotheses

• Must be TESTABLE
• Relates two variables
• Ifthenbecause
• IF a variable is manipulated a certain way, THEN
  another variable will respond this way BECAUSE of
  this reason.
• Forces you to think about what results in an
  experiment will look like
• SUPPORT or REJECTED!!

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Choose two and write a plausible hypothesis from
these predictions

• Chocolate may cause pimples.
• Salt in soil may affect plant growth.
• Plant growth may be affected by the color of the
  light.
• Bacterial growth may be affected by temperature.
• Ultra violet light may cause skin cancer.
• Temperature may cause leaves to change color.

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Important terms

• Important terms
• Independent (manipulated) variable (IV)
  condition or event under study, what you change
  (manipulate) in the study
• Dependent (responding) variable (DV) condition
  that could change under the influence of the
  independent variable (measure this)
• Controlled variables (CV) conditions which could
  affect the outcome of the experiment so they must
  be held constant (unchanged) among groups.

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Important terms (ctd.)

• experimental group group(s) subjected to the
  independent variable
• control group group not subjected to the
  independent variable, used as measuring stick
• reproducibility producing the same result
  consistently to verify result. Procedures should
  describe your experimental design in enough
  detail for others to perform the same experiment
  in the exact manner.

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What does this look like?

• Problem Does a certain brand of dog collar repel
  fleas?
• Hypothesis If , thenbecause.a.
• IV What is being manipulated?
• DV What are we measuring?
• CVs What do we need to keep the same in order
  for the experiment to be valid?

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What does this look like?

• Problem Does a certain brand of dog collar repel
  fleas?
• Hypothesis
• If this collar is used on dogs, then fleas
• will be repelled because fleas will
• respond in a negative way to chemicals
• on the collar.
• IV- having a collar
• DV- presence of fleas
• CV- list as many as you can!

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• Experimental group ?
• Control group ?

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Now to test

• Construct a flowchart (procedures)
• Set of instructions you will follow
• Controlled experiment
• Will have IV, MV, and CV naturally included
• Will have some form of quantitative or
  qualitative data collection

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Experimental Design

• Obtain 500 dogs of various breeds from local
  shelters.
• Have vet weed out the 200 dogs with the most
  fleas.
• Count number of fleas on dogs and average.
• Randomly assign individuals to 2 groups.
• Group A experimental (those with King collars).
• Group B control (no collars)
• Board dogs in identical environments . Give them
  identical amount and type of food. Give identical
  care. Only change the manipulated (independent)
  variable one group gets to wear the King collar
  and the other group does not.
• After two weeks count and average the number of
  fleas in Group A and B, separately.

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Experimental Design (Procedure) for ONE
prediction that you hypothesized on earlier..
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• Data
• Results
• Dogs wearing the King collars were virtually free
  of fleas after the 2 wk period compared to the
  dogs without the collars which had about the same
  number of fleas as when the experiment began

Group Average number of fleas (t 0) Average number of fleas (t end of Week Two)
Control group 500 515
Experimental group 500 50
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Conclusion

• Support or reject hypothesis
• Cite data from your data table
• Ex. As seen in the data table, the number of
  fleas in the treatment group with a collar
  decreased.
• Give value and meaning to the data and results
• Identify possible sources of error, explain how
  sources may have affected results.

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What would a well-written conclusion to this
experiment look like?
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III. Scientific Method In Action

• I want to market a new type of cat food for cats
  that will make them shed less. But first I have
  to see if it really works.

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I want to market a new flea collar for cats that
is a natural remedy-no harsh chemicals. But first
I have to see if it really works.

• GROUP WORK
• What are your MV and RV?
• List possible CV.
• Ifthenbecause hypothesis.
• Flowchart (procedure) accounting for MV, RV, and
  CV. What type of data will you collect?
• Data table.
• Results analysis.
• Support or reject hypothesis in conclusion.

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Scientific Method Review

• Definition
• A procedure for processing and understanding
  certain types of information
• Steps ( KNOW THESE!!!)
• state the problem
• gather information(make observations)
• Formulate hypothesis
• perform experiments (record and analyze the data)
• State a conclusion

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Scientific Measurement

• In Scientific investigation we ALWAYS use the
  metric system
• Mass Gram (g/mg)
• Weight Newton (N)
• Length meter (mm/cm/m)
• Volume Liter (mL/L)

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• Important terms
• Independent (manipulated) variable condition or
  event under study (choose 1)
• Dependent (responding) variable condition that
  could change under the influence of the
  independent variable (measure this)
• Controlled variables conditions which could
  effect the outcome of the expt so they must be
  held constant between groups.

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• experimental group group(s) subjected to the
  independent variable
• control group group not subjected to the
  independent variable, used as measuring stick
• reproducibility producing the same result
  consistently to verify result. It is therefore
  important to describe your experimental design in
  enough detail for others to perform the same
  experiment.

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Second Example

• Observation polar bears are white, you wonder
  why this is so
• Hypotheses
• Match arctic landscape for
  protection/predation
• White fur may reduce heat loss in warm-blooded
  animals
• Maybe polar bears are unable to produce
  melanin therefore they are white as result

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• Prediction polar bears which are white will
  capture more prey than those which are dark
• IV color of bears
• DV number of prey
• Experimental Design spray paint 5 polar bears
  dark(experimental Group)/leave 5 white(control
  group) Track prey capture for 8 weeks

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Effect of Polar Bear coat color on prey capture
Color of Bear White Dark
Number of Prey 12 7
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Probability and Statistics

• Probability an attempt to measure and predict
  the likelihood of an event
• Statistics allow you to evaluate comparisons
  between experimental and control groups

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Effect of Polar Bear coat color on prey capture
Color of Bear White Dark
Mean Number of Prey captured 12 7
Mean sum the values, divide by the number of
values
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• Assumptions factors thought to be true for the
  investigation but have not been verified or
  controlled
• Commonly accepted information
• Thought to be held constant but not controlled
• Factors beyond the investigators control because
  of technical or time considerations
• Incorrect assumptions invalidate an experiment!

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• Assumptions
• 1. All of the bears are equally hungry
• 2. Spray painting the bears has no effect on
  their behavior etc. accept to make them stand out
  on the ice
• 3. Our sample of bears is a good representation
  of the polar bear population in general

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Statistics

• Sample Size of observations necessary to have
  a reliable representation of a population
• Confidence Limits estimates that reflect the
  reliability of your mean (average)
• Probability your sample is similar to other
  random samples of that population