UNIT 1: The Science of Life
BIG IDEA: Biology is the study of
living things and their characteristics,
using the tools of science
Part1 – How do we know
if something is alive?
Characteristics of Life
1.
2.
3.
4.
5.
6.
7.
Cellular Organization
Use Energy for Metabolism
Growth and Development
Respond to Stimuli
Homeostasis
Reproduce
Heredity
Cellular Organization
• A cell is the smallest unit capable of
all life functions
• Levels of Organization:
Cells  Tissues  Organs  Organ
Systems Organism
A
B
C
Use Energy
 Energy is needed to run life sustaining
chemical reactions, like movement,
growth, and repair.
 Metabolism is the sum of all these
reactions.
Metabolism
• Metabolism manages the energy and
material resources in a cell.
• There are two basic types.
Catabolic
• Break down large molecules
• Releases/ Stores energy
• For example, cellular respiration is
the process that breaks down sugar
molecules into small energy storing
molecules
Anabolic
• Build larger molecules
• Uses energy
• For example, protein synthesis is the
building of large proteins from
smaller molecules called amino acids.
Growth and Development
• Growth: increase of living matter
(making more cells)
• Development: change into mature
adult
Response to Stimuli
• Stimulus: a change in the environment
• Organism respond and react to changes
around them
• For example, animals run from
predators.
• Think of stimuli you react to.
Homeostasis
• Homeostasis: to maintain the same
internal environment in response to
changes in the external environment
• What internal changes does your body
regulate?
Homeostasis
• Some examples: temperature, water
and salt levels, blood sugar levels
Reproduction
• Process by which organisms make
more of their own kind
• Necessary for the survival of the
species
• Asexual and sexual
Heredity
• Organisms pass hereditary
information in genes to their offspring.
• Genes are encoded in the molecule
called DNA
• Allows for adaptations and changes
through time
Tell what characteristics of life each item
has.
•
•
•
•
•
•
Seed
Volcano
Chicken egg
Bread dough
Moldy bread
A branch off a tree
DO NOW
• Think of a characteristic of life that a
nonliving object might display and
explain what it is.
Tools Used by Biologists Study
Living Things
A. Scientific Method
B. Microscope
C. Metric System
Scientific Method
Identify the Problem/Purpose
•Often developed from observations
made of nature.
Hypothesis and Prediction
•A hypothesis is a proposed explanation
for the stated problem.
•It must be testable!
• Then scientists can make a prediction
for the outcome of your experiment.
•“Predictions can be stated as “If….
Then…” statement.
Design an Experiment
•Use a controlled experiment to
test your hypothesis.
•Keep all the test conditions
the same except for the variable
you are testing
Record
Observations/Data/Results
• Collect data in the form of
measurements and observations
about experiment.
•Reported in metric/SI units
Two types of Data
Quantitative
• Data that uses
numerical values,
measurements
• E.g. mass,
temperature
Qualitative
• Data that uses
descriptions.
• E.g. color, odor,
texture
Analysis
•Explain your observations, data,
and results.
•List the main points that you
have learned.
•Was your hypothesis correct?
Conclusion
•Answer your problem/purpose
statement.
•What would be the next question
to ask?
• * Remember! Your hypothesis is
never PROVEN true. It is either
rejected or not rejected.
Share the Information
• Publish your findings in journals.
Theory
• Many accepted hypotheses that
explain a similar topic form a
theory.
• May be revised or replaced!
Designing a Controlled Experiment
• A controlled experiment
compares a control group against
an experimental group.
• A control group provides a
normal standard that is used to
compare with the experiment
group.
• The experimental group is the
same as the control group, except
for the one variable that is being
tested.
• The independent variable is the
factor that is being tested, which
changes from the control group to
the experiment group. It is
chosen by the scientist.
• The dependent variable is the
result of the experiment and is
the factor that is observed and
measured. It depends on what is
tested.
• Why does a good experiment control for
variables?
Metric System
SI units
Scientists Report Measurements
as…
• Mass =
gram
• Volume =
liter
• Length =
meter
Prefix
Abbreviation
Factor of Base Unit
giga
G
1,000,000,000
mega
M
1,000,000
kilo
k
1,000
hecto
h
100
deka
da
10
--deci
--d
1
0.1
centi
c
0.01
mili
m
0.001
micro
μ
0.000001
nano
n
0.000000001
Angstrom**
Å
0.0000000001
pico
p
0.000000000001
Converting SI units
• To move from a LARGER unit 
SMALLER unit => MULTIPLY
• To move from a SMALLER unit 
LARGER unit => DIVIDE
• Multiply/Divide by POWERS OF 10
SI units are in POWERS OF 10,
• to multiply move the decimal to the
right.
• to divide, move the decimal to the
left.
Move the Decimal
• 1.0 kg = 1000.0 g = 1,000,000.0 mg
• 1 mm = 0.1 cm = 0.001 m = 0.000001 km
• 4.5678 kg = 4567.8 g = 4567800 mg