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BIOLOGY: Chapter 1


BIOLOGY: Chapter 1 The Science of Biology – PowerPoint PPT presentation

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Title: BIOLOGY: Chapter 1

BIOLOGY Chapter 1
  • The Science of Biology

1.1 The Science of Biology
  • Science is basically two things
  • A body of knowledge an accumulation of things we
    have learned about the universe
  • A process an organized way of gathering and
    analyzing evidence

Goals of science
  • The goal of science is to provide explanations
    for events in the natural world
  • Learning about science involves understanding
    what we know, but also means understanding what
    we DONT know
  • Uncertainty is part of the scientific process and
    is limited by our technology and methods

The Scientific Method
  • An organized process used to answer a question
  • Start with a testable hypothesis
  • Repeatable experiments
  • Conclusion must be supported by the data
    scientists sometimes overreach their experiments
    and jump to conclusions

The Scientific Method
  • Background research to understand the state of
    knowledge of the subject before you begin What
    is already known about the topic? What types of
    methodology have been used in similar
    experiments? Thorough background research is
    what makes the educated guess educated ?

The Scientific Method
  • Form a testable hypothesis based on your
    background research
  • Design a repeatable experiment using the
    appropriate controls and variables (only
    manipulate one variable at a time!)
  • Conduct the experiment and record data
  • multiple trials
  • samples size must be appropriatebigger is

The Scientific Method
  • 5. Analyze the data statistical analysis and
    graphing (how different is different?!)
  • 6. Form a conclusion use your data analysis to
    determine if your hypothesis was supported
  • 7. Report your results scientific research
    journals, conferences, etc

Example of a scientific hypothesis
  • Null hypothesis (Ho) The male and female
    students have the same IQ
  • Alternative hypothesis (Ha) The male and female
    students have significantly different IQ scores
  • Must use statistical analysis to show

Example of a scientific hypothesis
  • Control (population) Avg IQ score 100
  • Male test group (n10) Avg IQ score 101
  • Female test group (n10) Avg IQ score 102
  • Are these two results truly different? Depends on
    the sample size and the range must use
    statistics to determine, but probably not!

Controls and variables
  • Control group exposed to the same conditions as
    the experimental group with the exception of the
    experimental variable the control group is the
    standard against which the experimental groups
    are compared
  • Independent variable the condition that is
    tested (ie the thing you change in the
  • Dependent variable the condition that results
    from changing the independent variable (ie what
    is observed or measured)

DRY MIX How to graph results
  • D dependent variable
  • R also called the responding variable
  • Y graphed on the Y axis
  • M manipulated variable (what you change)
  • I also called the independent variable
  • X graphed on the X axis

Writing experimental procedures
  • Must be clearly written so that anyone can follow
    your instructions
  • Numerical order, like writing a recipe
  • Use sizes, amounts, units of measure
  • Full sentences with punctuation!
  • Include safety procedures, set up and disposal
  • Make sure to include number of trials, sample
    sizes, etc

  • Results should be given in both graphs/charts and
    written form
  • Extensive discussion attempts to make sense of
    what you found
  • What does the data mean?
  • What kinds of things made sense or not?
  • Problems or other questions that arose?

  • Was your hypothesis supported?
  • Do not overreach the limits of your study
  • The case of the biting dogs

Recommendations/Future studies
  • Addresses possible solutions to problems you
  • Things you would like to do differently or repeat
    in a different way
  • Offshootswhat other questions did your
    research raise? This is how most real research is
  • Some researchers work their entire careers on the
    basis of one original question ?

Publication/peer review process
  • Peer reviewed literature is often very specific
    to certain disciplines (ie scientific journals)
  • Process involves sending drafts of manuscripts to
    experts in the field who review it anonymously
    and make recommendations
  • Edits and revisions are the norm, sometimes very
  • Often takes up to a year or more
  • Helps to keep science honest and as correct as

1.2 Science in context
  • Attitudes of a good scientist
  • Curiosity
  • Skepticism
  • Open-mindedness
  • Creativity

1.2 Science in context
  • Theory a well-tested explanation that unifies a
    broad range of observations and hypotheses and
    enables scientists to make accurate predictions
    about new situations
  • Theories are based on much EVIDENCE and supported
    by DATA

Theories vs. laws
  • Theories do not become laws!
  • Laws (such as ideal gas laws or Newtons laws)
    are concise and specific descriptions of how some
    aspect of the natural world is expected to behave
    in certain situations.
  • Theories are more dynamic and complex. They
    encompass a greater number of ideas and
    hypotheses than laws and are constantly
    fine-tuned through the process of science.

  • Scientists must make every effort to avoid bias
    (bias is not scientific!)
  • Bias does creep into science through funding and
    political issues, but should be seen and
  • The case of the disappearing whales of Prince
    William Sound

Exxon Valdez spillPrince William Sound AK1989
1.3 Studying Life
  • How do biologists determine if something is
    living or nonliving? (biotic or abiotic)
  • They must meet certain criteria
  • Some things (VIRUSES!) meet some but not all of
    the criteriagrey areas exist

Characteristics of Living Things
  • Based on a universal genetic code (DNA)
  • Grow and develop
  • Respond to their environment (stimulus
  • Made up of cells
  • Reproduce (asexually or sexually)
  • Maintain a stable internal environment
  • Obtain and use energy and materials (metabolism)
  • Taken as a group, living things evolve.

Three Domains of Life
6 kingdoms of organisms
Biotic vs. Abiotic