Transcript Steps of the Scientific Method

“Biology: The Science of Life”
Objectives
• To give a general understanding of the life
science terminology.
• To recognize characteristics of organisms.
• To learn why we study biology.
What is Biology?
• Biology is the study of life!
Why do we study biology?
• To learn about the different
types of living things around us
• To learn how each species fits
into the pattern of life
• To appreciate the diversity of
life
What kinds of questions can
biology answer?
• What? (What are some features of this
living thing?)
• Why? (Why does this living thing
possess such features?)
• How? (How do these structures work?)
How are we connected to other
living things?
• Living things don’t exist in isolation;
they depend upon other living things
• Living things interact in a variety of
ways and reasons (food, protection,
etc.)
List 3 different types of work that
biologist do.
• They work in a variety of
environments
• Laboratories (bacteria, DNA, disease)
• In the field (artic, deep-sea studies,
etc.)
• Radio tracking (tigers)
What is Life?
• Sometimes not so easy to recognize;
biologists have formulated a list of
characteristics by which we recognize
living things.
• Anything that possesses all
characteristics of life is an organism.
4 Characteristics of Living
Things
1. Living things are organized – show
an orderly structure; have specialized
parts that perform particular functions
-is when all structures & functions of
an organism come together to form an
orderly living system
(humans – cell, body systems, etc.)
2. Living things reproduce- reproduction
is not essential for the survival of an
individual organism; however, it is
essential for the continuation of an
organism’s species
(species – a group of similar-looking
organisms that can interbreed &
produce)
3. Living things change during their lives:
Growth: increase in the amt. of living
material & the formation of new
structures (conception, 2, 4, 8-cells, etc.)
Development: all of the changes that take
place during the life of an organism
(maturity level, puberty)
4. Living things adjust to their
surroundings:
(example: our bodies adjust to heat or
cold; going down to the beach, moving
up north; however, it is a slow process)
4. continued
• Any condition in the environment that
requires an organism to adjust is known as a
stimulus- ex. weather.
• A reaction to a stimulus is called a
response- you adjust or die
• stimulus – it’s raining,
• response – get an umbrella
4. continued
• Any structure, behavior, or internal
process that enables an organism to
respond to stimuli & better survive in
an environment is known as an
adaptation.
• For example: many nocturnal animals
possess large eyes for efficient vision
at night; bats have radar, camels (feet,
eyelashes, hump)
4. continued
• An organism must respond to stimuli
from its internal environment also.
• Factors such as infection & external
temp. can cause changes in body
temp., quantities of water, nutrients,
etc.
• Such changes can disrupt proper
functioning.
4. continued
• Adjustments to internal stimuli help
organisms maintain a steady internal
environment
• An example is human sweating:
Stimulus: It’s hot outside
Response: You sweat and your face
gets flushed which cools the body &
helps your body maintain proper
internal temperature
4. continued
• The regulation of an organism’s
internal environment to maintain
conditions suitable for life is called
homeostasis (to maintain balance)
5 Parts of an
Experiment
Parts of an experiment
• Independent variable – What you control in
an experiment. The setup of an experiment.
What is the difference in the groups?
Dependent variable – The results. Your results
are dependent on the set up of the
independent variable. What has to be
measured?
• Constants - anything in an experiment that
remains the same throughout. What stays the
same throughout the experiment?
Groups in an experiment
• Control Group – the group with normal
conditions. The group nothing is being
done too. Only 1. Not always present.
• Experimental Group – The group with
different conditions. The group that is
being tested. Can be more than 1
The Strange Case of BeriBeri
In 1887 a strange nerve disease attacked the people in the Dutch East Indies.
The disease was beriberi. Symptoms of the disease included weakness and
loss of appetite, victims often died of heart failure. Scientists thought the
disease might be caused by bacteria. They injected chickens with bacteria
from the blood of patients with beriberi. The injected chickens became sick.
However, so did a group of chickens that were not injected with bacteria.
One of the scientists, Dr. Eijkman, noticed something. Before the
experiment, all the chickens had eaten whole-grain rice, but during the
experiment, the chickens were fed polished rice. Dr. Eijkman researched this
interesting case. He found that polished rice lacked thiamine, a vitamin
necessary for good health.
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State the Problem.
What was the hypothesis?
How was the hypothesis tested?
Should the hypothesis be supported or rejected based on the experiment?
What should be the new hypothesis?
How Penicillin Was Discovered
In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in
culture dishes. He noticed that a mold called Penicillium was also growing in some
of the dishes. A clear area existed around the mold because all the bacteria that had
grown in this area had died. In the culture dishes without the mold, no clear areas
were present.
Fleming hypothesized that the mold must be producing a chemical that killed the
bacteria. He decided to isolate this substance and test it to see if it would kill bacteria.
Fleming transferred the mold to a nutrient broth solution. This solution contained all
the materials the mold needed to grow. After the mold grew, he removed it from the
nutrient broth. Fleming then added the nutrient broth in which the mold had grown to
a culture of bacteria. He observed that the bacteria died.
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Identify the problem.
What was Fleming's hypothesis?
How was the hypothesis tested?
Should the hypothesis be supported or rejected based on the experiment?
This experiment led to the development of what major medical advancement?
Scientific Method
The scientific method is an organized,
logical approach used to solve a problem or
answer a question.
The scientific method is a list of
steps that are not set in stone but rather used as a
guide for solving problems or answering
questions.
Steps of the Scientific Method
1. State the Problem or Question
– Before the problem or question can be stated
you must do something first…
• Make an observation –
– Observations use all or some of the senses (sight, taste,
feel, hearing, or smell) to gather information.
– Observations lead to questions and help identify problems.
– In your research you will focus on only one question that
you came up with in your observations.
Steps of the Scientific Method
2. Gather Information
– Research background information to determine what is
already known
3. Generate a Hypothesis
– A hypothesis is a possible answer to a question or
problem.
– A hypothesis must be in the form of a testable
statement.
• Example:
– Correct – The amount of sunlight a plant is exposed to will affect
how tall the plant will grow.
– Incorrect – Maybe the height of a plant has something to do with
the amount of sunlight.
Steps of the Scientific Method
4. Test the Hypothesis
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A hypothesis must be tested to see if it is valid
Data collected during the experiment will either
support or reject the hypothesis.
A hypothesis is tested using a controlled
experiment.
Steps of the Scientific Method
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A controlled experiment has the following:
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Constants – Variables that are kept the same during the
experiment in both the experimental group and the control
group.
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Independent Variable – The variable that is purposely changed
in the experiment.
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Example: The amount of sunlight a plant receives.
Dependent Variable – The variable that changes due to the value
of the independent variable.
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Example: Type of plant, soil used, size of pot…
Example: The size of the plant.
Experiment must be repeated more than once to make sure the
results are valid.
Steps of the Scientific Method
5. Collect & Analyze Data
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During the experiment data is collected.
After the experiment, data is organized and
analyzed.
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Create graphs
Identify patterns & trends
Steps of the Scientific Method
6. State a Conclusion
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Did the data
collected support the
hypothesis?
7. Share
results/findings
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May generate a new
question
The Nature of Inquiry
THE END