The World of Life Science Chapter 1 Holt Science and Technology

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					The World of Life Science
           Chapter 1
   Holt Science and Technology
        Life Science, 2001

Science Reading Introduction
       Miss Elizabeth
    MLK JHS 2006-2007
          What is Science
1.Classifying – so when reading we will
  classify text by identifying the main
  idea and details
2.Experimenting – so when reading we
  will look for sequencing the order of
3.Drawing Conclusion – so when reading
  we will draw conclusion as we read
4.Writing up experiment results so after
  reading we will write an expository essay.
  This is an essay that is meant to inform
  the reader. Some examples:
  –   Tell what happened when . . .
  –   Write a report on . . .
  –   Explain how to . . .
  –   Describe how to for . . . .
 Some links to reference:
5.Observing/inferring so when reading we will
  distinguish between cause and effect.
  Usually scientists observe the effect and
  infer its cause.
6.Determining cause and effect so also when
  reading we will determine cause and effect –
  the main cause and the main effect.
7.Comparing and contrasting so when reading
  we will look for things that are similar and
  that are different. Comparing and
  contrasting allow readers and scientists to
  group similarities and separate differences.
• Is a two way street – not just a one
  way with teacher providing
  information. Education is two way
  with half from teacher providing
  information and half your response.
• Response is more than getting the
  right answer which requires memory
  but not deep thinking where a
  backhoe was used to build the second
          Science Notebook
• We will have ―unit notebooks‖ to keep
  all our papers together, but also a
  journal where we can gather our
  thoughts and our questions. To help
  with developing our questioning or
  interrogation skills copy the following
  T-chart to the inside of your first
  science journal.
Question and Response
What is “on the     What is “between the lines”
•Direct              •What words, phrases do you like? What clues
information found     do they give about the meaning or purpose or
in a portion of       sense of the passage?
text you read –      •What questions do you have as you are
just the facts.       reading? Where do these questions lead?
•What is             •What words are unfamiliar? What do they mean?
happening in the       What do they add?
―story‖; what are    •What main concepts begin to emerge for you?
the parts of the
―argument‖?          •How do the parts of the ―story‖ or ―argument‖ or
                     ―concept‖ fit together?
                Wonderings – What is “off the page”
•Wondering: what do I wonder abut now?
•Memory: what does this remind me of?
•Application: what areas of my everyday life incorporate these ideas?
•Feeling: how do I feel about this ―story‖
•Imagination: what story can you imagine and write about?
Structured Notes to help get the main
 ideas and important details together.
In the beginning of the class we will
 work through structured notes
 before reading is assigned. You will
 have directed reading worksheets to
 complete while reading. Once
 through those we will practice ―deep
 reading‖ when we are really thinking
 about what we are reading.
    Chapter 1: The World of Life Science
•     What do you think – complete
      sentences mean complete thoughts
     1. What tools do life scientist use?
     2. What methods do scientist use to
        study life science?
     3. Can anyone become a life scientist?
         1.1 Asking About Life
  – Wondering – questions that just pop
    into your mind.
  – Observing the world around us, being
    curious. Leads to questioning our
  – Life Science is the study of living thing.
• It all starts with a question.
  – Easy to find in your backyard or touring
    the world
• Looking for Answers
  – Science takes people with curiosity and
     • Who? Anyone can investigate the world
       around us. Women and men from any
       cultural, ethnic, or income background can
       become life scientists.
     • Where? Doing investigations in a
       laboratory is an important part of life
       science, but science can be studied in many
       other places too.
     • What? Life Scientists or Biologists
       specialize in many different areas.
    What Life Scientists Study
• how organisms function and behave,
• how organisms interact with each
  other and with their environment,
• how organisms reproduce and pass
  traits from one generation to the
• how organisms change over time and
  what are the origins of organisms
             Why Ask Why?
•   Two ways listed in your textbook
     1. to combat disease and
     2. to protect the environment.
•   Can you think of some other
    reasons why study life science?
•   Life science affects you and all the
    living things around you.
         Combating Disease
– Polio is a disease of the brain and informs
  that causes paralysis.
– We don’t see many people now but before
  1960, it infected 1 in every 3,000 Americans.
– It was life scientists who discovered way to
  prevent the spread of the polio virus and we
  are now vaccinated.
– Children get 4 doses of IPV, at these ages:
  A dose at 2 months A dose at 6-18 months
  A dose at 4 months A booster dose at 4-6 years
   Current diseases that scientists
      search for ways to fight

• Tuberculosis caused by Mycobacterium
 tuberculosis, a slow-growing bacteria that
 thrive in areas of the body that are rich
 in blood and oxygen, such as the lungs.
• AIDS caused by HIV (human
 immunodeficiency virus)
• Cystic Fibrosis caused by an inherited
    Protecting the Environment
• Why protect the environment?
• What environmental problem can you
  think of?
• Pollution can harm our health and the
  health of other animals and plants.
  When we cut down trees we alter and
  sometimes destroy the habitat of
  other creatures or the climate.
 1.2 Thinking Like a Life Scientist
• The Scientific Method
  – Is a series of steps that is used to
    answer a question or solve a problem.
  – The steps are applied creatively meaning
    sometimes scientists come back to a
    step, do the steps in a different order,
    or skip a step depending on the question
               The steps:
– Ask a question: based on observations
– Form a hypothesis: a possible explanation for
  what you have observed.
– Test the hypothesis: by conducting
– Analyze the results: collected from
– Draw conclusions: from the results
– Communicate results: to other scientist in
  writing and in presentations
When researchers use the scientific
 method, can they repeat or switch the
 order of steps or do they need to keep
 them always exactly the same? Explain.

• Scientists can repeat or switch the order
  of steps as needed.
• The Scientific Method is a map and there
  is more than one way to reach your
Ask a question: based on observations
• Observations can take many forms:
  – Measurements of length, volume,
    temperature, time or speed.
  – Descriptions of how loud or soft a sound is or
    the color or shape of an organisms; what
    something does, how it moves, or its patterns
    of behavior.
  – Scientist have to be careful when making
    observations that the observations are
    accurately made and recorded.
  – Observations become data.
     Form a hypothesis: a possible explanation
            for what you have observed
•   When scientists form hypotheses they
    think logically, creatively, and keep in mind
    what they already know.
•   A hypothesis must be testable by
    experiment or observation.
•   A hypothesis that is not testable may not
    be wrong, but it is not USEFUL because it
    can’t be proved or disproved.
•   Different scientists can have different
    hypotheses for the same question.
•   Hypotheses are based on predictions.
• A prediction is a statement of cause and
  effect that can be used to set up a test
  for a hypothesis.
• Predictions are usually stated in an ―If
  ………, then…….‖ format.
• Once predictions are made, scientists can
  design experiments to see which
  predictions, if any prove to be true and
  support the hypothesis.
  Self Check – Which of the following
      statements is a hypothesis?

1. Deformed frogs have been found in
   the United States and Canada.
2. Insecticides and fertilizers caused
   the frog deformities.
3. Frogs can easily absorb pollutants
   through their skin.
What do scientists use to answer a
 question or solve a problem?
  – the scientific method.
  – their imagination.
  – their creativity.
  Test the hypothesis: by conducting
• Scientist try to design experiments that
  will clearly show whether a particular
  factor was the cause of an observed
• A factor is anything in an experiment
  that can influence the experiment’s
  outcome. Here we have lots of causes.
• Scientists control experiments so that
  only one factor at a time is tested.
• In a controlled experiment there is a
  control group and one or more
  experimental groups.
   – All the factors in the control group and
     the experimental groups are the same
     except for one.
     • The one factor that differs is called the
  – Because the variable is the only factor
    that differs between the control group
    and the experimental groups,
     • scientists have more certainty that
       variable is causing the differences
       observed in the results.
• In order to be certain about the
  conclusions of an experiment,
  scientists should repeat the same
  experiment many times.
• Designing a good experiment requires
  a lot of thought and planning.
               Self Check
Henry is testing the effects of different
   antibacterial soaps on the growth of
   bacteria. His experiment contains
   several jars of the same strain of
   bacteria. Which of the jars described
   below is the control group?
  1. To Jar A, Henry adds two drops of Super
  2. To Jar B, Henry adds two drops of Anti-B
  3. To Jar C, Henry adds no soap.
                Self Check
• A scientist wants to study the possible
  side effects of a new medicine, how
  should he/she set up this experiment?
  (How many groups, how much medicine,
  control group?)
  – how many groups? Depends on the kinds of
    patients that will be treated by the drug.
  – how much medicine? Depends on potencies
    that have been established by other tests.
  – control group include a control group
   that receives no medicine
  Analyze the results: collected from

• Ways to analyze results:
  – organizing your data into tables, charts
    and graphs.
  – doing calculations to learn more about
    your results.
               Math Break
Finding the average of a group of numbers
  is one way to analyze data.
• Dr. Brown found that 3 seeds kept at
  25°C sprouted in 8, 8, and 5 days.
  – To find the average number of days that it
    took the seeds to sprout, she added 8,8, and
    5 and divided their sum by, the number of
    subjects (seeds) in the group.
  – She found the average number of days to
    sprout at 25°C was 7 days.
       Math Break Self Check
• Dr. Brown also found that 3 seeds kept at
  30°C sprouted in 6,5, and 4 days.
• What’s the average number of days that
  it took these seeds to sprout.
Draw conclusions: from the results
• When drawing conclusions, scientist have
  to decide whether the results of the
  experiment have shown that a prediction
  was correct or incorrect.
• When scientist find that a hypothesis is
  not supported by the tests:
  – they must try to find another explanation for
    what they have observed.
  – they realize that they have eliminated one
    possible factor.
 What to do with a wrong hypothesis?
• If a tested hypothesis does not
  produce the expected results,
  – don't trash the results—it might lead
    to another discovery.
• Proving that a hypothesis is wrong is
  just as helpful as supporting it.
  – Because either way, the scientist has
    learned something.
 Communicate results: to other scientist in
      writing and in presentations
• After concluding that your tests
  support your hypothesis, you should
  publish the results:
  – so that other scientists can learn from
  – so that other scientists may repeat the
    experiments to see if they get the
    same results.
   Scientific Knowledge Changes
• Scientists continue to discover new
  information all the time.
• Each time a prediction is proven true,
  a hypothesis gains more support.
• A theory is a unifying explanation for
  a broad range of hypotheses and
  observations that have been supported
  by testing.
      1.3 Tools of Life Scientists
•   Tools for seeing
•   Computers
•   Systems of Measurement
•   Safety Rules
              Tools for Seeing
• Magnifying tools enables scientists to
  observe smaller details:
  – Compound Light Microscope
    • Compound because it has two lenses an ocular
      lens and an objective lens.
    • Uses light to illuminate
  – Electron microscope
    • Uses tiny particle called electrons to either
      bounce off or penetrate a non-living sample.
      Very high magnification.
            Chapter 1 Tools
• There are two types of microscopes
  that we will discuss:
  – Compound light microscopes - uses light
    and two lenses
  – Electron microscopes - have better
    resolution than compound light
    microscopes and uses an electron beam.
       Microscopy Vocabulary
• Resolution – the ability to clearly
  distinguish the individual parts of an
• Magnification – the enlargement of a
  structure by means of bending the
  light that passes through lenses in
  the case of a light microscope or a
  beam of electrons in case of an
  electron microscope
                    middle of the lens
• Convex lens: the ______
  is thicker than the __________.
• Concave lens: the ______ of the lens
 is thicker than the __________.
           Other Seeing Tools
• X-rays, Magnetic resonance imaging (MRI),
  and Computed Tomography (CT)
  – High energy photons pass through a sample and
    an image is created.
• First built in 1946 – sixty years ago
  – Not commercially available until 1980’s.
  – Allow complex calculations and graphic
    representation of data used to decide whether
    differences in experimental data are
     Systems of Measurement
•   The International System of Units,
    universally abbreviated SI (from the
    French Le Système International
    d'Unités), is the modern metric system
    of measurement.
•   Developed by the French Academy of
    Sciences in the late 1700’s.
•   A system of measurement based on the
    number 10.
Scientists use the International
 System of Units because it:
  – makes sharing results among scientists
  – contains units that are based on the
    number 10.
  – standardizes a method of recording
            Common SI Units
•   Length – meter
•   Volume – cubic meter = m3
•   Area – square meter = m2
•   Mass – gram
•   Temperature – degrees Celsius = °C
                SI prefixes
• King – kilo - 1000
• Henry – hecto - 100
• Died – deko - 10
• Drinking – deci – 1/10 = 0.1
• Chocolate – centi – 1/100 = 0.01
• Milk – milli -1/1000 = 10-3 = 0.001
Even smaller
     Micro – 10-6 = 0.0000001
     Nano – 10-9 = 0.000000001
            Safety Rules
• Safety First is the motto.
• Having experiments in class requires
  good behavior – and good attention.
• Always follow your teachers
• Don’t take shortcuts

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