Chapter 1
THE SCIENCE OF BIOLOGY
http://www.bozemanscience.com/biology
Section 1: What is Science?
— The goal of science is to investigate and
understand the natural world, to
explain events in the natural world, and
to use those explanations to make
useful predictions.
— Science - is an organized way of using
evidence to learn about the natural
world.
Thinking Like A Scientist
—  Why won’t the car start?
Thinking Like a Scientist
—  Observation - The process of gathering
information about events or processes in a careful,
orderly way. (Usually involves the senses,
particularly sight and hearing.)
•  Data - Information gathered from observations.
¡ Quantitative
- Expressed as numbers
¡ Qualitative - Expressed as characteristics
Thinking Like a Scientist
—  Inference - A logical interpretation based
on prior knowledge or experiences.
Explaining and Interpreting the Evidence
—  After the initial observation, scientists will propose
one or more hypothesis.
—  Hypothesis - A proposed scientific explanation for
a set of observations
¡  Often
referred to as an “educated guess”
¡  Only useful if it can be tested
Scientists generate hypotheses using prior
knowledge, (what they already know); logical
inference; and informed, creative imagination.
Explaining and Interpreting the Evidence
—  Scientists often collaborate in teams to work on
complex questions or problems.
Science is a way of knowing
•  Science is a never ending process.
•  New tools, techniques, and discoveries can lead to
new scientific understandings.
•  Look at the picture below…What might a scientist do
with such a discovery?
Science and Human Values
—  Today, scientists contribute information to
discussions about health and disease, and about the
relationship between human beings and the living
and nonliving environment.
http://blip.tv/
reelscience/thescientific-methodof-oz-6118389
Notebook #1
1.  What does science study?
2.  What is the difference between
qualitative and quantitative data?
3.  What is a hypothesis?
4.  When trying to solve complex
problems, how do scientists often
work?
Section 2: How Scientists Work
•  For thousands of years, people have noticed that
living things have magically appeared from nonliving things.
¡  Maggots appear on dead animals or rotting meat.
¡  Mice appear on piles of grain.
¡  Beatles appear on cow dung.
•  Scholars from that era called this
phenomenon Spontaneous Generation.
Designing an Experiment
•  The maggot theory lasted until 1668 when
an Italian physician, Francesco Redi,
designed an experiment to test his
hypothesis.
•  Redi believed that maggots were the larva
form of house flies. To test this hypothesis,
Redi designed the following experiment.
Designing an Experiment
https://www.youtube.com/watch?v=WzbHOY5fGqc
A Controlled Experiment
•  Whenever possible, a 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.
•  This is called a controlled experiment.
•  Independent Variable (Manipulated
Variable) - the variable that is deliberately
changed (Gauze).
•  Dependent Variable (Responding Variable)
- the variable that is observed (Maggots appear).
Recording and Analyzing Results
•  Scientists must keep written records of their
observations, or data, that occur during their
experiment.
•  In the past, most results were written in notebooks
or journals. They also could have drawn pictures
like the following.
—  Today, records can be kept with
computers, tablets, and other
electronic devices.
Drawing a Conclusion
•  Scientists use the data from an
experiment to evaluate the
hypothesis and draw a valid
conclusion.
•  Was the hypothesis supported or
not supported by the results?
The Scientific Method
Repeating Investigations
•  Many times after a scientist publishes their work, other
•
•
•
•
•
scientist will retest their ideas.
In the mid 1700’s, an English scientist named John Needham
tested Redi’s ideas using another organism called
“animalcules” (Discovered by Anton van Leeuwenhoek).
Needham believed spontaneous generation could occur under
the right conditions.
He sealed a bottle containing gravy and heated to kill any
living thing.
Several days later, he examined the bottle and saw it was filled
with activity.
He inferred “these little animals can only have come from the
gravy.”
http://www.bozemanscience.com/scientific-method
Spallanzani’s Test
—  Lazzaro Spallanzani read Redi and Needham’s work.
He believed Needham did not heat the gravy enough
and decided to do the following experiment.
Section 1-2
Gravy is boiled.
Flask is
open.
Gravy is teeming
with microorganisms.
Gravy is boiled.
Flask is
sealed.
Gravy is free of
microorganisms.
Pasteur’s Test
•  Another scientist named Louis Pasteur wanted to disprove
spontaneous generation. He stated that Spallanzani’s
experiment wasn’t valid because living things need air to
survive. The sealed bottle of gravy prevented that.
•  Pasteur used a flask that had a curved neck which allowed
air in but kept microorganisms out.
https://
www.youtube.
Section 1-2
com/watch?
v=63IoOLXmz
Kg
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with
microorganisms.
Notebook #2
1.  What is spontaneous generation? Is it a
scientific explanation that is well supported
today?
2.  What is a controlled experiment?
3.  What is the difference between the
independent variable and the dependent
variable in an experiment?
4.  Why is it important to repeat experiments?
Section 3: Studying Life
Interest Grabber
Shells and Snowflakes
How can we distinguish between living and nonliving things, such
as a radiolarian (left) and a snowflake (right)? A radiolarian is a
tiny living thing that is covered with a glasslike shell and lives in
the ocean. A snowflake is a crystal made of frozen water.
Interest Grabber (continued)
Work with a partner to answer the following
questions.
1. What are some similarities between the
snowflake and the glass shell of the
radiolarian?
2. What are some differences between the
snowflake and the glass shell?
3. Would you classify the shell as a living thing
or a nonliving thing? Explain your answer.
Characteristics of Living Things
—  Living things…
1.
2.
3.
4.
5.
6.
7.
8.
Are made up of units called cells
Reproduce
Are based on a universal genetic code
Grow and develop
Obtain and use materials and energy
Respond to their environment
Maintain a stable internal environment
(homeostasis)
Change over time
Characteristics of Living Things
Section 1-3
Characteristic
Examples
Living things are made up of units called
cells.
Living things reproduce.
Living things obtain and use materials and
energy.
Many microorganisms consist of only a single cell.
Animals and trees are multicellular.
Maple trees reproduce sexually. A hydra can
reproduce asexually by budding.
Flies produce flies. Dogs produce dogs. Seeds from
maple trees produce maple trees.
Flies begin life as eggs, then become maggots, and
then become adult flies.
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.
Living things are based on a universal
genetic code.
Living things grow and develop.
http://vimeo.com/
15407847
Characteristics of Living Things
—  Cell – collection of living matter enclosed by a barrier that
separates the cell from its surroundings
—  Sexual reproduction – cells from two parents unite to
produce the first cell of the new organism
—  Asexual reproduction – process by which a single
parent reproduces by itself
—  Metabolism – combination of chemical reactions through
which an organism builds up or breaks down materials
—  Stimulus – signal to which an organism responds
—  Homeostasis – process by which organisms maintain a
relatively stable internal environment
—  Evolution – change in a kind of organism over time
Figure 1-21 Levels of Organization
Section 1-3
Levels of Organization
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
Section 1-3
Organism Individual living
thing
Bison
Tissues, organs,
Groups of and organ systems
Cells
Brain
Nervous tissue
Cells
Nervous system
Smallest functional
unit of life
Nerve cell
Groups of atoms;
smallest unit of
Molecules most chemical
compounds
Water
DNA
Notebook #3
1.  What are the 8 characteristics of living
things?
2.  What is a cell?
3.  What is the difference between sexual
and asexual reproduction?
4.  What is metabolism?
5.  What is homeostasis?
Section 4: Tools and Procedures
A Common Measurement System
— Most scientists use the metric system
when collecting data and performing
experiments.
— Metric system – decimal system of
measurement based on certain physical
standards and on multiples of 10
https://
www.youtube.com/
watch?
v=MekxJse2vgs
Metric System
Microscopes
—  Light microscopes – produce magnified images
by focusing visible light rays
¡
Compound light microscope – uses two lenses to form an
image
—  Electron microscopes – produce magnified
images by focusing beams of electrons
Transmission electron microscope (TEM) – shines a
beam of electrons through a soecimen
¡  Scanning electron microscope (SEM) – scan a narrow
beam of electrons back and forth across the surface of the
specimen
¡
Laboratory Techniques
—  Cell culture – group of cells grown in a nutrient solution
from a single, original cell
—  Cell fractionation – technique in which cells are broken
into pieces and the different cell parts are separated
Notebook #4
1.  What is the metric system and why
have scientists around the world
agreed to use it?
2.  What is the difference between a light
microscope and an electron
microscope?
3.  What is a cell culture?
4.  What is cell fractionation?