1. Chapter 1
The Science of biology

2. 1-1 What Is Science? What is the goal of science? So what is science?
To understand the world around us.
So what is science?
An organized way of using evidence to learn about the natural world.

3. Thinking Like a Scientist
Scientists record observations.
Information gathered using the senses. Ex: there is a person standing in the front of the room.
Data
Qualitative data – descriptive ; ex: rough or smooth
Quantitative data – numerical; counted or measured ; ex: 12 apples or 52.5 grams.
Most experiments contain both types of data.
An inference may follow an observation.
A logical interpretation based on prior knowledge or experience.
Ex: the person is a teacher.

4. Observation and Inference
Section 1-1
Statement Observation Inference
Object A is round and orange. X
Object A is a basketball.
Object A is a basketball.
Object B is a table-tennis
ball.
Object C is a soccer ball.
Object C is round and black and white.
Object C is larger than Object B.
Object B is smooth.
Object B is a table-tennis ball.
Each object is used in a different sport.

5. Note the differences
In laboratory exercises, record observations NOT inferences
Inferences may be used when writing the conclusion to your lab.
Let’s test your observation skills…
You’ll need a piece of paper and a writing utensil

7. Answer these questions
Are there cars parked on the sides of the road?
What color is the pickup truck driving in the road?
Any minivans around?
What does the green sign say?
Were there any pedestrians on the road?
What's the speed limit?

8. Question 1
Are there cars parked on the sides of the road?

10. Question 2
What color is the pickup truck driving in the road?

12. Question 3
Any minivans around?

14. Question 4
What does the green sign say?

16. Question 5
What's the speed limit?

18. Question 6
Are there any pedestrians on the road?

20. Observation vs. Inference
On the next slide, state whether the statement is an observation or an inference.

21. 1. There is a representation of a face on one side of the coin.
2. The Latin word "Dei" means "God."
3. The coin was made by deeply religious people.
4. The date 1722 is printed on one side of the coin.
5. The coin was made in 1722.
6. The face on the coin is a representation of the nation's president.

22. Try This…
Record observations for one minute.

23. Explaining and Interpreting Evidence
What is a hypothesis?
A proposed explanation for an observed set of facts.
Must be testable by performing controlled experiments and collecting data
Some hypotheses may be supported, and others may not be supported.

24. Science as a Way of Knowing
Science is an ongoing process – it continually changes.
Good scientists are skeptics; they question new as well as existing ideas.

25. 1-2 How Scientists Work
About 2000 years ago a Roman poet wrote these directions for producing bees:
Kill a bull during the first thaw of winter.
Build a shed.
Place the dead bull on branches and herbs inside the shed.
Wait for summer. The decaying body of the bull will produce bees.

26. Spontaneous Generation
Aristotle proposed 2300 years ago that a “vital force” was present in the air that caused living things to arise from nonliving things.
This was called spontaneous generation.
In the 1600s, scientists began to question this theory.
To test this theory, scientists used the scientific method.

27. Flowchart Designing an Experiment State the Problem Analyze Results
Section 1-2
Designing an Experiment
State the Problem
Analyze Results
Form a Hypothesis
Draw a Conclusion
Set Up a Controlled Experiment
Publish Results
Record Results

28. A Different Hypothesis
In the 1600s, people believed rotting meat produced maggots spontaneously.
In 1668, Francesco Redi proposed that flies were landing on the meat and laying eggs, which hatched into maggots.
He conducted a controlled experiment to test his hypothesis.
In a controlled experiment only one variable is tested at a time.

29. Redi’s Experiment on Spontaneous Generation
Section 1-2
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time
Several
days pass
Independent Variable:
gauze covering that
keeps flies away from
meat
Dependent Variable:
whether maggots
appear
Maggots appear
No maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

30. Biogenesis
Redi concluded that living things could only come from other living things.

31. Repeating Investigations
In the 1700s John Needham, an English scientist, conducted an experiment to test Redi’s idea (skeptic).
He said animalcules could arise from gravy, contradicting Redi’s work.
He boiled gravy, sealed the flask, and days later microorganisms appeared in the flask thus “supporting” the theory of spontaneous generation.

32. Repeating Investigations
An Italian scholar, Lazzaro Spallanzani, didn’t believe Needham’s results (skeptic).
He said Needham didn’t boil the gravy long enough, so he repeated his experiment with modifications…

33. Figure 1-10 Spallanzani’s Experiment
Section 1-2
Gravy is boiled.
Flask is
open.
Gravy is teeming
with microorganisms.
Flask is
sealed.
Gravy is free of
microorganisms.
Gravy is boiled.

34. Biogenesis again…
Spallanzani concluded that nonliving gravy did not produce living things. The microorganisms came from the air.

35. Repeating Investigations
By the 1800s, some scientists still supported the theory of spontaneous generation.
They felt sealing the flask cut off the “vital life force” in the air.
In 1864, Louis Pasteur settled the debate.
He designed a flask that could keep airborne microbes out without being sealed.

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

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

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

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

40. Pasteur’s Work
Louis Pasteur’s work revolutionized the food and wine industry.
The process of heating foods until microorganisms are killed before packaging is called “Pasteurization”.

41. Alternative Investigations
Controlled experiments are not always possible.
Field studies - animals
Medical research – clinical trials
Environmental research
Scientific methodology is still used:
Large study groups
Controlled variables

42. Theories
The theory of biogenesis developed from many experiments that tested the hypothesis that new organisms come from existing organisms.
When a hypothesis becomes very well supported it is considered a theory.
A theory is defined as a well tested explanation that unifies a broad range of observations.
Can theories change?
Can a theory be proven true?

43. 1-3 Studying Life Biology –
-bios = life
-logy = study of
Living things share certain characteristics.

44. Characteristics of Living Things
Section 1-3
Characteristic
Examples
Living things are made up of units called cells.
Many microorganisms consist of only a single cell. Animals and trees are multicellular.
Living things reproduce.
Maple trees reproduce sexually. A hydra can reproduce asexually by budding.
Living things are based on a universal genetic code.
Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.
Living things grow and develop.
Flies begin life as eggs, then become maggots, and then become adult flies.
Living things obtain and use materials and energy.
Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.
Living things respond to their environment.
Leaves and stems of plants grow toward light.
Living things maintain a stable internal environment.
Despite changes in the temperature of the environment, a robin maintains a constant body temperature.
Taken as a group, living things change over time.
Plants that live in the desert survive because they have become adapted to the conditions of the desert.

45. Branches of Biology Zoologists – Botanists – Paleontologists –
animals
Botanists –
plants
Paleontologists –
ancient life
Microbiologists –
microscopic life
Immunologists –
Disease
Ecologists –
Organisms and their environment

46. Levels of Organization
Living things may be studied on many different levels.
The largest and most complex level is the biosphere.
The smallest level is the molecule.

47. Levels of Organization
Section 1-3
Biosphere
The part of Earth
that contains all
ecosystems
Biosphere
Ecosystem
Community and
its nonliving
surroundings
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
Community
Populations that
live together in a
defined area
Hawk, snake, bison, prairie dog, grass
Population
Group of
organisms of one
type that live in
the same area
Bison herd

48. Levels of Organization continued
Section 1-3
Organism
Individual living
thing
Bison
Tissues, organs,
and organ systems
Groups of
Cells
Nervous tissue
Brain
Nervous system
Smallest functional
unit of life
Cells
Nerve cell
Groups of atoms;
smallest unit of
most chemical
compounds
Molecules
Water
DNA

49. 1-4 Tools and Procedures Scientists use a common measurement system:
The metric system, or SI
Some standard units of measurement are:
Length –
Meter
Ruler or meter stick
Volume –
Liter
Graduated cylinder or pipet
Mass –
Gram
balance
Temperature
Celsius
thermometer

50. Analyzing Data
Data tables are used to stay organized when recording data.
Graphs are used to make data easier to interpret and see trends (patterns).

51. Making a Graph From A Data Table
Section 1-4
Making a Graph From A Data Table
Water Released and Absorbed by Tree
Absorbed
by Roots
(g/h)
Released
by Leaves
(g/h) 20
Water released by leaves
Time 15
8 AM 1 2
Relative Rates (g/h) 10
10 AM 1 5
12 PM 4 12 5
2 PM 6 17
Water absorbed by roots
4 PM 9 16
6 PM 14 10
8 AM
10 AM
12 PM
2 PM
4 PM
6 PM
8 PM
8 PM 10 3
Time

52. Microscopes
Devices that produce magnified images of structures that are too small to see with the unaided eye.
Three common microscopes are:
Light microscope
Can magnify up to 1000X
Useful for viewing cells
Electron microscope
Can magnify up to 100,000X
Useful for seeing parts of cells
Dissecting (stereo) microscope
Can magnify up to 5X
Useful for dissections

56. Laboratory Techniques
Two common techniques for studying cells are cell culture and cell fractionation.
Cell culture
Cells are grown in sterile dishes
Especially useful for growing stem cells
Cell fractionation
Cells are broken apart in a blender
Cell parts are separated in a centrifuge