Science of Biology Notes

1
Science of Biology Notes
2
What is Science? (1-1)

• The root sci- means to know. Science is one
  way of investigating the world in which we live.
  Science strives to
• explore and understand the natural world,
• explain events in the natural world, and
• use those explanations to make useful
  predictions.
• Are some things unpredictable?

3
Things that are not science include things like

• Art
• Religion
• Literature
• Opinion

4

• Science can only concern itself with testable
  things and\or observable things

5
Is scientific knowledge a set truth?

• No!
• In our scientific explanations, we explain how
  things work using the knowledge we have to
  explain natural phenomena
• When our knowledge base changes, our explanation
  may change

6
What is Science?

• Scientists use observations based on facts to
  gather data.
• They also use known data to make inferences (a
  logical interpretation of the data based on past
  experiences).

7
Determine in the picture if it is an observation
(O) or an inference (I)
O

1. _____ There are 2 doors.
2. _____ The people are fighting because someone
   ate their cookies.
3. _____ One door is closed.
4. _____ They are hitting each other hard.
5. _____ Glass is broken.

I
O
I
O
8
How Scientists Work

• The Scientific MethodScientists solve
  problems, but the method may vary based on the
  problemThe three types of investigations
• Experimental Research Design
• Correlation
• Investigation

9

• Descriptive Investigations - involves describing
  and/or quantifying parts of a natural system
• Comparative Investigations - involves collecting
  data on different populations/organisms, or under
  different conditions (e.g. time of year,
  locations, temperature), to make a comparison
• Experimental Investigations - involves a process
  in which a "fair test" is designed in which
  variables are manipulated, controlled and
  measured in an effort to gather evidence to
  support/refute a relationship

10
Steps to Experimental Scientific Investigation
(The Scientific Method)

• 1. Observe make an observation of the world
  around you. There are two kinds of observations
• Qualitative observation descriptive observation
• Ex The plant is green.
• Quantitative observation a numerical
  observation.
• Ex The flask contains 12.45 ml. There are 4
  pennies.

11
Determine if the statement is qualitative (A) or
quantitative (B).
A

• _____ The sky is blue.
• _____ There are 4 clouds.
• _____ There are 3 hills.
• _____ The first hill is small.
• _____ The clouds are small.
• _____ There are a total of 38 birds.

B
B
A
A
B
12

• 2. Ask a question based on your observation,
  ask a question to investigate.
• Ex. Redi asked the question How do new living
  things, or organisms, come into being?
• 3. Research - Look in books, journals and the
  internet to make additional observations and
  research about the questions you made from your
  observation.

13

• 4. Formulate a hypothesis - Propose a
  scientific explanation to the question being
  observed and researched. The statement must be
  testable. (Which is best? does not lend itself
  to being tested). At the end of the
  investigation, you will either accept or reject
  your hypothesis.
• Ex. If meat is left uncovered, then flies will
  leave eggs on the meat, creating maggots.

14

• 5. Perform a controlled experiment - Develop and
  use the experimental design to test your
  hypothesis. Whenever possible, the hypothesis
  should be tested by an experiment in which only
  one variable is changed at a time. All other
  variables should be kept unchanged, or controlled.

Testing fertilizers on plant growth? Keep all
other factors constant!
15

• Variables Factor being tested
• Controlled- Variables that are kept constant
• Independent- Variable being manipulated (in a
  graph found on the x-axis or the horizontal axis)
• Dependent- Variable that responds (in a graph
  found on the y-axis or the vertical axis)
• Control Group the group where the independent
  variable is NOT applied. Meaning, nothing is
  changed. Used for comparison.

16
A way to remember variables

• Dependent
• Responding
• Y - axis
• Manipulated
• Independent
• X - axis

17
Repeat your experiment!

• The more times you do it, the more accurate your
  data and results will be!!

18

• 6. Observe again - Collect data (measurements)
  and perform analysis on the data using graphs and
  charts

19

• 7. Draw conclusions - State whether or not the
  evidence supports the hypothesis based on your
  data and analysis.
• Please notice that we do not prove hypotheses!
  Proof exists when the chance for error is 0.
  There is always some chance for error (no matter
  how small it is) and this existence of chance
  error means we cannot prove anything in true,
  honest, science.

20

• 8. Report back to the community Experiments
  results can be used by other to help them with
  their own experiments. This is what keeps
  science progressing.

21
What is the difference between a hypothesis, a
theory, and a law?

• A hypothesis is a possible explanation for a set
  of observations. It has not yet been thoroughly
  tested.

22
What is the difference between a hypothesis, a
theory, and a law?

• A theory is a well tested explanation that
  unifies a broad range of observations.
• A theory explains observations simply and
  clearly, and predictions can be made from them.
• It is widely accepted by the scientific
  community.

Theory of Plate Tectonics
23
What is the difference between a hypothesis, a
theory, and a law?

• A law is a summary of observed natural events
  they are less comprehensive than theories and
  normally are associated with a mathematical
  expression. It is also widely accepted by the
  scientific community.

Law of Universal Gravitation
24
Tools and Procedures

• Biologists use metric measurement (the SI system)
  to gather and interpret data.
• SI is the universal measurement system.

25
Tools and Procedures (1-4)
26
Conversions

• The metric system is universal measurement system
  based on the number 10. The meter is the
  distance value, the gram is the mass value, and
  the liter is the volume value.

27
Graphing- how a scientists shows patterns in data
collected.

• There are several kinds of graphs not all of
  them are useful for data communication. Which
  type of graph is appropriate for which situations?

28
Line Graph

• Line graph - compares two things in which items
  on one axis affect the items on the other axis.
  If you are comparing anything to time, it is
  usually a line graph.
• (Ex. Amount of CO2 in the atmosphere over the
  last 6 decades)

29
Line Graph
30

• Bar graph - compares two or more values. (Ex.
  Number of students with red hair in each class)

31
Bar Graph
32

• Pie Chart- effective in showing proportions or
  percentages of a whole thing. (Ex. Comparing
  the percentage vote that each candidate received
  in the election)

33
Pie Chart
34
Graphing

• Always draw lines with a ruler, use pencil, and
  use map pencils when necessary. Make sure your
  graph contains all components
• Title tell what you are comparing or displaying
  (be descriptive).
• X-axis label and give scale.
• Y-axis label and give scale.
• Key give meanings of the symbols and colors
  used on the graph.
• Data points clearly marked, and label them if
  you do not have grid lines.

35
1) Light microscope produces magnified images
by focusing visible light rays. This microscope
can be used to magnify up to 1000 times
36
2) Electron microscope produce magnified images
by focusing beams of electrons. This kind is
used to magnify tens and hundreds of thousands of
times for extremely small object like a virus.
The hair on the leg of a fly(magnified by a
factor of 1000)
Salt crystals on the antennas of an
insect(magnified by a factor of 5000)