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
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
information found
in a portion of
text you read –
just the facts.
•What is
happening in the
“story”; what are
the parts of the
What is “between the lines”
•What words, phrases do you like? What clues
do they give about the meaning or purpose or
sense of the passage?
•What questions do you have as you are
reading? Where do these questions lead?
•What words are unfamiliar? What do they mean?
What do they add?
•What main concepts begin to emerge for you?
•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?
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
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
• Convex lens: the ______ of the lens
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
Fly UP