The Science of Biology
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Science – the process to understand the world around us.
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Biology – the study of life
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Bio means life
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Ology means study of
Biologists Study the Diversity of Life
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Why Study Biology?
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Lead to advances in medical treatment and disease
prevention.
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Help preserve species in danger of disappearing
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Teach you how humans function
Characteristics of Living Things
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Living organisms must have all 7 characteristics of life to
be considered living
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7 Characteristics of Living Things:
1. All living things are made of cells
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A cell is the smallest unit of an organism that
can be considered alive
2. All living things contain DNA
3. All living things reproduce
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Reproduction is not essential for the survival of an
individual organism, but it is essential for the survival
of the species.
4. All living things grow and develop
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Growth – an increase in size and the formation of new
structures.
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Development – all of the changes that take place
during life.
5. All living things obtain and use energy
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Organisms need energy to grow, develop and
reproduce
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Metabolism – chemical reactions through which an
organism carries out its life processes
6. All living things adapt and evolve
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Adaptation – respond to stimuli for better survival
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Evolution – the gradual accumulation of adaptations
over time.
7. All living things maintain a stable internal environment
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Homeostasis – regulation of an organisms internal
environment to maintain conditions suitable for its
survival
The Methods of Biology and Science
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Science is a way of thinking. It is an ordered way of
finding answers to problems or questions.
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Scientific Method – common steps that scientists use to
gather information and answer questions.
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Scientific Method has 5 steps:
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1. Collect observations and state the problem.
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Use your five senses to make observations.
2. Form a hypothesis – an explanation for a question or a
problem that can be tested.
3. Plan and Perform MULTIPLE Experiments.
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Perform the experiment many times to reduce the
chance of error.
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You must always have a control.
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Control - the group in which all conditions are kept
the same and you can compare your results
against.
4. Observe and Record Results.
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Make tables, charts, graphs
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Do you see any patterns or trends?
5. Draw Conclusions
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Does the data support your hypothesis?
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What errors occurred in your experiment?
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What would you do different next time?
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Form a Theory
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Theory – a hypothesis that is supported by a large
body of scientific evidence.
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No theory is considered absolute truth.
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As new evidence is uncovered a theory may be
revised or replaced.
It becomes a Law after many years of holding true.
Two Variables Involved in Testing
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Independent Variable
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It is the variable you mess with or what you can
change
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Value does not depend on change in the other value.
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Goes on the X axis
Dependent Variable
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The variable you measure or what you can’t directly
control.
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Value depends on change in the other value.
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Goes on the Y axis
Graphing
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The X axis is horizontal
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The Y axis is vertical
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What Makes a Good Graph?
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Make sure your graph has a title
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Make sure the axis is labeled with units of
measurement
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Use all of graph paper.
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Key
L
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Effect of Enzyme Concentration on Enzyme Activity
Enzyme
Concentration
H2O2
Depth
Your Data
Time
Your Data
Rate
Class Data
Avg. Rate
0 units/ml (0%)
100mm
0.0sec
0 mm/sec
0.0mm/sec
20 units/ml (20%)
98mm
31 sec
3.2 mm/sec
2.98mm/sec
50 units/ml (50%)
103mm
18 sec
5.7 mm/sec
5.48mm/sec
80 units/ml (80%)
100mm
14 sec
7.1 mm/sec
7.39mm/sec
100 units/ml (100%)
110mm
12 sec
9.2 mm/sec
8.42mm/sec
Effect of Enzyme Concentration on Enzyme Activity
10
9
8
7
My Results
6
Class Avg.
Enzym e Reaction
5
Rate (m m /sec)
4
3
2
1
0
0
20
50
80
Enyzm e Concentration (units/m l)
100
Effect of Enzyme Concentration on Enzyme Activity
B
A
R
G
R
A
P
H
Enzyme
Concentration
H2O2
Depth
Your Data
Time
Your Data
Rate
Class Data
Avg. Rate
0 units/ml (0%)
100mm
0.0sec
0 mm/sec
0.0mm/sec
20 units/ml (20%)
98mm
31 sec
3.2 mm/sec
2.98mm/sec
50 units/ml (50%)
103mm
18 sec
5.7 mm/sec
5.48mm/sec
80 units/ml (80%)
100mm
14 sec
7.1 mm/sec
7.39mm/sec
100 units/ml (100%)
110mm
12 sec
9.2 mm/sec
8.42mm/sec
Effect of Enzyme Activity on Enzyme Concentration
9.5
9
8.5
8
7.5
7
6.5
6
5.5
Enzyme
Reaction Rate 4.55
(mm/sec)
4
3.5
3
2.5
2
1.5
1
0.5
0
My Results
Class Avg.
0
20
50
80
100
Enyzme Concentration (units/ml)
Energy Sources and Uses
P
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Other Uranium
Sources 4%
7%
Oil
43%
Natural
Gas
24%
Coal
22%
Natural Gas
Coal
Oil
Other Sources
Uranium
Kinds of Research
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Quantitative Research
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Experiments that result in counts, measurements, or
numerical data
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Data may be used to make a graph or table.
Qualitative (Descriptive) Research
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Observational data that is written descriptions of
what scientists observe.
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Useful because some experiments aren’t appropriate
for quantitative research.
Microscopes
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2 important concepts of microscopes:
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Magnification – to make an image appear larger.
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Resolution - shows details clearly.
Light Microscopes
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Use a beam of light passing through one or more
lenses
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Compound light microscopes use two sets of lenses
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Use compound microscopes to study living cells
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As magnification increases the resolution decreases.
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Electron Microscope
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Use electrons instead of light
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Can magnify more than light microscopes
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Living cells cannot be viewed
2 Types of Electron Microscopes
1. Transmission Electron Microscope
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Reveals its internal structures.
2. Scanning Electron Microscope
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See 3-D images of cell surfaces
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Reveals surface structures.
Image Comparison
Compound
Cyclotella 1000X
Bacteria 1000X
Scanning Electron Microscope
Cyclotella 1000X
Bacteria 10,000X
Transmission EM
Viruses
Eyepiece or Ocular Lens
Arm
Rotating Nose
Piece
Objectives
Stage Clips
Stage
Coarse Adjustment
Knob
Diaphragm
Light
Fine Adjustment
Knob
Base
How to Get an Image in Focus
1. Put on low power objective
2. Turn the coarse adjustment knob to move stage all the way
up
3. Turn the coarse adjustment knob away until the image is in
focus
4. Turn the fine adjustment knob to get a clearer and sharper
image
5. Change to the medium objective
6. Only use the fine adjustment knob to bring the image into
focus. Do not use the coarse knob.
7. Change to the high objective.
8. Use the fine adjustment knob to bring the image into focus.
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Parfocal – once the image is in focus on low power, the
image will remain in focus.
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Total Magnification
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The eyepiece has a lens in it that magnifies 10X
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The low power objective magnifies at 4X
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The medium objective magnifies at 10X
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The high objective magnifies at 40X
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To find the total magnification you must multiply the
eyepiece and the objective you are on:
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Example: 10X * 4X = 40X
10X * 10X = 100X
10X * 40X = 400X