Biology I Notes
Chapter 1—Characteristics of Life
Definition of Biology
Bio = life
–ology = study of
Life is defined by 7 Characteristics:
1. All living things are made of cells
-Cells are the smallest units of life capable of
all functions
2. All living things can reproduce
3. All living things perform the chemical
reactions necessary to obtain and use the
energy that allows them to function—
Metabolism
4. All living things must maintain a stable
internal environment—Homeostasis
7 Characteristics of life continued
5. All living things are able to pass on
characteristics to their offspring-Heredity
6. Species must be able to adapt and
change as their environment changes—
Evolution
7. All living things must live and interact
with other organisms.
Salt on a pretzel
Human hair cut
• A strand of human hair is about 100 µm
wide
Cricket leg
Red
blood
cells are
7 µm in
diameter.
Red blood cell, platelet, T-lymphocyte
Red cells: nonnucleated/contain hemoglobin (contains iron and allows the cell to carry
oxygen to other parts of the body)/carry carbon dioxide away from peripheral tissue to
the lungs where it can be exhaled
infection-fighting white blood cells classified in two groups: granular and agranular.
Granulocytes are formed in bone marrow; agranulocytes are produced by lymph
nodes and spleen. Two types of agranulocytes: lymphocytes, which fight disease by
producing antibodies and thus destroying foreign material, and monocytes.
Platelets: tiny cells formed in bone marrow/ necessary for blood clotting.
Types of Microscopes (p 52-54)
Compound Light Microscope (CLM)
-light microscopes that use two
lenses
(ocular and objective)
Stereo Microscope
Electron Microscopes
-more powerful than CLM
-cannot be used on living specimen b/c it requires a
vacuum chamber
-up to 200,000x magnification
TEM (transmission electron microscope)
-electron beam is directed at a thin slice of a
specimen stained with metal ions
-shows internal detail
SEM (Scanning electron microscope)
-Shows surfaces in great detail
Scanning Tunneling Microscope
-uses a probe attached to a computer
-can be used on living specimen
SEM
For more samples go to:
http://academic.udayton.edu/ShirleyWright/SEM/Samp
les.htm
TEM
The TEM can view objects that are 60,000
times smaller in diameter than a human
hair $475,000 Portland State Univ.
Compound light->
TEM
SEM
The Scientific Process
–
–
–
Collecting Observations-using your senses
Asking Questions-What is the effect of _ on _?
Forming hypotheses and making predictions
•
–
Confirming predictions through experimentation
•
–
–
–
If _______ changes, then it will affect _______.
Writing a procedure
Collecting/Analyzing data –tables and graphs
Drawing Conclusions
Publishing results in scientific journals
(magazines)
Observation/Question/Hypothesis
• Observing problems, or using senses
• Question
– What is the effect of ____ on ____?
• Hypothesis
– If /then or cause/effect statement.
Experiments need 2 groups:
Control group —receives no experimental treatment
Experimental group —identical to the control group
except for one factor, or variable. (receives the
experimental treatment)
>This variable that is being tested or changed by the
experimenter is called the independent variable or
manipulated variable
? What did I change about the control/experimental
group?
>The variable that is measured is called the dependent
variable or responding variable
? What data did I measure and collect ?
ALL other variables must remain the same, or
constant. (also sometimes called controls)
WHY DO I NEED CONSTANTS?
• Other variables could affect the results, so
we must control those by keeping them
the same. We want to see the effect of the
IV on the DV without other factors
interfering.
– TO MAKE SURE THAT WE ARE ONLY
TESTING ONE VARIABLE!!!
Procedure
• 3 or more specific steps answering the
question.
• Someone could repeat the experiment
exactly as you did.
• How did you:
– change the IV?
– Measure the DV?
– Hold other variables constant?
• Be detailed!!!!!!!!
Tables
• Needs these items:
– IV with units
– DV with units
– Place to record data
– Periods of time shown if needed
*Choose the one that best displays the data.
IV DV
IV
DV
DV
Time DV
IV Time
Time IV
Graphs
Line Graphs
•
Best for data that changes with time (continuous)
•
x-axis contains the independent variable
•
y-axis contains the dependent variable
Bar Graphs
•
Useful when comparing data for several individual items
•
Set-up is the same as a line graph
Rules for graphing
•
Always label the axes
•
Always include units of measure
•
Always include a title
•
Number scales must be consistent
TITLE: The effect of (the IV) on (the DV)
• DRY MIX
• Dependent or
Responding variable –
Y axis
•
•
•
•
•
•
What is the:
IV?
DV?
Title?
Manipulated or
Interval on the x axis?
Independent variableInterval on the y axis?
X axis
“When there’s a key, it’s the IV!”
? What is the:
IV?
DV?
Variable on the x axis?
Variable on the y axis?
Title?
Unit on the x axis?
Unit on the y axis?
What group does the triangular data represent?
Conclusion (finally!)
• Analyze data (mean, median, mode) if
needed
• Restate hypothesis and support or refute it
using DATA
• Identify sources of error and explain effect
on results
• Make proposals for future investigations