1. THE SCIENCE OF BIOLOGY
Chapter 1

2. Understanding the Black Death
Killed 1/3 of the population in Europe
People in the 13th century thought it was caused by “bad air” or demons
How do we find out?
Why do we care?

3. The Goals of Science to investigate and understand nature
to explain events in nature
to use those explanations to make useful predictions
Investigations of disease led to antibiotics and antivirals

4. The Methods of Scientists
collect and organize information (data) in a careful, orderly manner
look for patterns in data
propose explanations that can be tested by examining the evidence

5. Observation Based on five senses: sight, hearing, taste, smell, touch
Quantitative – numerical
Ex- how many, how big, how fast
Qualitative – descriptive
Ex – color, texture, smell, behavior

6. Hypothesis
Good
Bad
1. Plants will grow taller when given Miracle Grow. 2. Girls will score higher on math tests than boys.
1. Plants will grow better when given Miracle Grow. 2. Girls are smarter than boys.
Logical, testable, tentative explanation for a set of observations or a possible answer to a scientific question
Arise from prior knowledge, logical inferences, or imaginative guesses

7. Testing hypotheses Can be done through further observation
Usually done through controlled experiments
A hypothesis proven to be wrong still adds to the body of scientific knowledge

8. THE CASE OF THE CHUNKY MILK
You wake up in the morning very thirsty. Accidentally, you reach over and grab the glass of milk you left out yesterday. After one swallow, you start gagging and want to throw up. What happened? How can we PROVE it?

9. Observations Smells nasty White in color
Looks chunky like cottage cheese
Tastes like
Feels warm
The gallon in the fridge is NOT expired yet

10. HYPOTHESIS TIME

11. BAD: The milk is bad.
GOOD: If the milk is allowed to sit out of the fridge for approximately 24 hours, then the milk will spoil.

12. Designing an Experiment
State the problem: milk tastes gross, looks chunky
Form the hypothesis: If the milk is allowed to sit out of the fridge for approximately 24 hours, then the milk will spoil.
Set up Experiment

13. Cup of milk in cool environment Cup of milk at room temperature
Leave a cup of milk out of the fridge for 24 hours and see what happens.
Cup of milk in cool environment
Cup of milk at room temperature
Variables involved in the experiment
Milk
Temperature
Amount of milk
Time
Independent (Manipulated)
Dependent (Responding)
What happens?

14. What are the results?
Accept or Reject Hypothesis

15. Scientific Method
There is a logical way of thinking found in all scientific experiments
Observe a problem
Ask a question
Create a hypothesis
Design a controlled experiment
Collect and analyze data
Share results

16. Spontaneous Generation
In the past, people thought life could just appear from non living matter
Ex – maggots just appear on meat

17. Redi’s Experiment
1668 – proposed hypothesis that the maggots came from flies
Tested hypothesis by placing meat in jars and covering some of the jars
Everything was controlled (kept the same) except the variable (covering jars)

18. Redi’s Experiment Uncovered jars Covered jars Maggots appear
Several
days pass
Maggots appear
No maggots appear

19. Types of Variables Independent: the variable being manipulated
Redi controlled the covering of the jars
Dependent: the variable that changes in response to the independent variable
The presence of maggots in Redi’s experiment

20. Spallanzani’s Experiment
Gravy is boiled.
Flask is
open.
Gravy is teeming
with microorganisms.
sealed.
Gravy is free of
microorganisms.
Tested Redi’s results
Boiled to kill microorganisms
What are the independent and dependent variables??

21. Pasteur's Experiment
Provided final proof that spontaneous generation did not occur

22. Pasteur's Experiment Figure 1-11 Pasteur’s Experiment Broth is boiled.
Section 1-2
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.
Go to Section:

23. Pasteur's Experiment What was Pasteur’s hypothesis?
Microorganisms would not just appear
Independent variable?
Curved neck of flask
Dependent variable?
Presence of microorganisms

24. A Theory in Science A very well supported hypothesis
When a hypothesis has been verified many times by different scientists, it becomes a theory
Redi’s, Spallanzani’s, and Pasteur’s experiments led to the theory of biogenesis (life comes from life)
Theories explain phenomena in nature

25. What makes something alive?
Is a book alive?
Is a tree alive?
Is a computer alive?

26. Characteristics of Life
Made of one or more cells
Reproduction – sexual or asexual
Contain RNA and/or DNA – universal genetic code
Growth (getting bigger) and development (changing, ex: puberty)

27. Characteristics of Life
Need energy – metabolism is the sum of all chemical reactions in body
Respond to their environment
Maintain homeostasis – stable internal environment
Evolve (change) over time

28. Tools and Procedures SI = System International
The international, metric standard for reporting units
Necessary to ensure scientific data can be interpreted by all scientists everywhere
Easy to use because it is based in 10
To convert between units, you only have to move decimals 

29. Metric Units Length Mass Volume Temper-ature Time Meter Gram Liter
Celsius
Second m g L C s
Length = distance
Mass = amount of matter in an object
Volume = amount of space an object occupies
Temperature = measurement of heat energy
Time = too abstract for me to define…

30. Tools of the Trade Metric Ruler
Measures in meters, centimeters, millimeters
Smaller lines mark mm
Longer lines mark cm

31. Tools of the Trade Graduated Cylinder
Measures liquid volume in Liters and milliliters
Measurement is made at the “meniscus,” the curve of the liquid line that occurs when a liquid is added

32. Tools of the Trade Thermometer Metric Scale
Measures in degrees Celsius
Metric Scale
Measures in grams or kilograms
Can be manual or electric

33. Metric Prefixes kilo hecto deka Base m,g,L deci centi milli k 1000 hdk 10 1 d
0.1 c
0.01 m
.001
m = meter
g = gram
L = liter

34. Some Common Examples… Mass Length Volume mg = milligram mm =
millimeter
ml or mL =
milliliter
g =
gram
cm =
centimeter
L =
Liter
kg =
kilogram
m =
meter
kl or kL =
kiloliter
km =
kilometer

35. Converting Metric Units
Metric conversions are WAY simple because the metric system is based in 10’s
Changing between metric units simply requires movement of a decimal.
Changing from the English to metric system requires the use of conversion factors (and usually a calculator!).

36. Let’s Practice Metrics 
1 m = ?cm
1 kg = ?g
1 mL = ?L
286 g = ?mg
48.7 mm = ?m
kg = ?hg
280,000 mg = ?kg
23 cc = ?ml
100
1000
0.001
286,000
0.0487
0.28 23