THE SCIENCE OF LIFE
Reference:
Modern Biology
CHAPTER 1
BIG IDEA
•Biology is the Study of
Life!
•Certain ‘themes’ unify
all Biological Sciences.
•Living things, no matter
how diverse, share
common characteristics.
Biology - The Study of Life
BIOLOGY-the study of all living things
(organisms like plants, animals, insects, bacteria,
humans).
EXAMPLES of Biological Sciences:
– Histology-the study cells and tissues
– Genetics-the study of how traits are
inherited
– Microbiology-the study of microorganisms
– Ecology-how organisms interact with each
other and their environment.
6 MAJOR THEMES OF BIOLOGY
The study of Biology is unified by
certain themes, or patterns that
connect all living things:
1.
2.
3.
4.
5.
6.
Cell Structure and Function
Stability & Homeostasis
Reproduction and Inheritance
Evolution
Interdependence of organisms
Matter, Energy & Organization
SECTION 1-1 UNIFYING THEMES OF BIOLOGY
Stability & Homeostasis
Cell Structure & Function
Reproduction & Inheritance
Interdependence of Organisms
Evolution
Matter, Energy & Organization
1. CELL STRUCTURE & FUNCTION
All organisms are made of and
develop from cells – the basic
unit of life.
•UNICELLULAR-made of only one
cell (amoeba, paramecium)
•MULTICELLULAR-made up of
many different types of cells
working together (tree,
spider, dog)
1. CELL STRUCTURE & FUNCTION
Unicellular – Each
new cell is
identical to the
parent. All
developing
organisms are
exact clones of
their parents.
DIFFERENTIATION
Multicellular –
Cells become
different from
each other as they
multiply. All
multicellular
developing
organisms are a
combination of
two parents, but
are different from
them – not clones.
1. CELL STRUCTURE & FUNCTION
Cell - One Name, Many Types
•All cells, no matter what kind, have
similarities, as well as differences.
•Certain cell structures determine the
function of the cell.
•Examples:
•Red Blood Cells – carry oxygen
•Plant cells – carry out photosynthesis
•Unicellular Microorganisms – carry
out ALL of life processes.
2. STABILITY & HOMEOSTASIS
All living things must maintain stable
internal conditions to survive.
Homeostasis - stable level of internal
conditions found in all living cells.
EXAMPLES:
•temperature
•water content
•food intake
•blood glucose levels
•sleep
3. REPRODUCTION & INHERITANCE
All organisms come from existing organisms.
They reproduce and transfer their hereditary
information to their offspring.
2 Types of Reproduction:
•ASEXUAL REPRODUCTION-heredity
information is not combined - only one
organism’s DNA is used. Offspring are
identical to parent.
EXAMPLES: bacteria and other unicellular
organisms
•SEXUAL REPRODUCTION- heredity
information (DNA)from two organisms from
the same species combine. Offspring are
different from both parents and from any
other offspring
EXAMPLE: monkey having a baby
Egg and sperm  zygote (fertilized egg).
3. REPRODUCTION & INHERITANCE
Organisms transfer their hereditary
information to their offspring in the form of
deoxyribonucleic acid (DNA) – the “book” of
life.
A gene is a short segment
of DNA that contains the
instructions for a
single trait.
Lung Cells vs. Thyroid Cell s
Each “turn on” different genes
vs.
3. REPRODUCTION & INHERITANCE
4. EVOLUTION
Populations of organisms evolve
or change over time.
Evolution -population of organism
changes over generations (time).
Natural selection is the most important
driving force behind evolution.
5. INTERDEPENDENCE OF ORGANISMS
All living organisms interact with other
living organisms and their non-living
environment.
5. INTERDEPENDENCE OF ORGANISMS
The branch of biology concerned with
these interactions is called Ecology.
Ecology-the study of how organisms
interact with each other and with their
environment.
6. MATTER, ENERGY & ORGANIZATION
All living organisms need a constant
supply of energy.
How organisms obtain, use and
transfer energy is a major topic of
study in biology.
ALL energy for life on earth comes
from
the SUN.
6. MATTER, ENERGY & ORGANIZATION
The MOST Important Factor Determining how many
and what kind of organisms that can live in an
environment is the amount of ENERGY Available.
• Autotrophs-organisms that can get energy by
producing their own food.
• EXAMPLES: plants and some
unicellular organisms
• Heteroptrophs-organisms that must get energy
by eating other organisms
• EXAMPLES: some unicellular organisms, all
animals and fungi
Take the Concept
Review Quiz 1_1 …
The World of Biology
DO NOW:
In your notebook, respond to the
following:
Suppose you discovered an
unidentified object on your way
home from school. How would
you determine if it is a living or a
nonliving thing?
THE CHARACTERISTICS OF LIFE
All organisms, no matter how different,
have certain characteristics in common
THE CHARACTERISTICS OF LIFE !
1. MADE OF CELLS
All living things are composed of
cells…
2. ORGANIZED
All living things are highly organized…
•They are organized at molecular and
cellular level.
•Cell structures (organelles) carry out
specific functions.
2. ORGANIZED
Levels of Hierarchy of
Biological Organization:
Cells  tissues
Tissues  organs
Organs  systems
Systems ORGANISM
2. ORGANIZED
3. USE ENERGY
All living things use energy…
•All organisms use energy to
grow, reproduce and make repairs.
•Metabolism-all of the chemical
processes that take place in a
living organism.
4. HOMEOSTASIS
All Living things maintain stable internal
conditions and respond to their
environment.
Remember: Homeostasis is maintaining
internal balance.
Response - reaction to input (stimulus)
from the world.
•May be simple or complex.
•EXAMPLE: Bird fluffing its feathers
to stay warm
5. GROW & DEVELOP
All living things grow and
develop…
5. GROW & DEVELOP
Growth is the increase
in the amount of living
material in an organism.
Development is the series of
changes an organism undergoes
in reaching its final
adult form.
6. REPRODUCTION
All living things reproduce…
•Create more of their own species.
•Essential to the survival of the
species…NOT of the reproducing
organism.
DO NOW
Compare and Contrast:
1. Make a chart that lists the six
characteristics of life.
2. Watch the following video clip,
IS IT ALIVE…OR IS IT??
3. Use the chart to help you
determine whether the object is
living or non-living. Support
your decision.
SCIENCE – LEARNING ABOUT THE WORLD
What is Science?
Science is a process that produces
a body of knowledge!
•Science is carried out because
people :
‐Wonder…
‐Are Curious…
‐Ask questions…
•That is the beginning of all
scientific research.
SCIENCE – LEARNING ABOUT THE WORLD
Knowledge from science
can be used to improve life.
Example: polio vaccine,
penicillin, genetically
enhanced food
Watch this Video
How simple ideas
lead to scientific
discovery
Respond to the video
in your notebook.
BIOLOGY AS A SCIENCE
METHODS OF SCIENCE
One of the best ways
to begin studying
science is to examine
how scientists try to
solve a problem or
answer a question
Whatever they study,
all scientists use
certain methods to get
answers!
METHODS OF SCIENCE
What is in
here??
METHODS OF SCIENCE
The Scientific Method
Scientist use certain methods in their
work…
The Scientific Method
A group of strategies or steps used to help
guide scientist to arrive at an answer to a
question or problem.
The Scientific Method
The Scientific Method has
approximately 6 steps:
1. Observation
2. Asking Questions
3. Collect Data
–
Research
4. Hypothesis (explains their
observations and can be tested!)
5. Experiment (testing your hypothesis,
Collecting, Organizing & Analyzing Data)
6. Conclusion & Communication
Step 1 & 2- Observations &
Questions
• 1- Use the 5 senses to perceive objects or
events.
• 2 - Ask a question
– Based on observations; one or more questions
are generated.
Step 3 – Research & Collect
Data
Research – a methodical investigation into a
subject in order to answer a question,
discover facts and to develop a plan of
action based on the facts discovered
Data – any and all information gathered
while researching an answer to a question
Step 4 – Forming a Hypothesis
Hypothesis-a possible explanation for what
was observed and why it should be true.
– It must be able to be tested and proven wrong
– If/then statement-often written in this form.
– Example: If giving a tomato plants “Tomato
Grow” plant food increases the size of the
tomatoes they produce, then tomato plants
feed “Tomato Grow” will produce larger
tomatoes.
Step 5- Experimenting
A hypothesis is often tested by carrying out
an experiment.
Most experiments in Biology are controlled
experiments
– performed to test your hypothesis (confirm
or disprove it)
– Based on a comparison of a control group
with an experimental group.
• Used to gather data under controlled conditions.
» Data-bits of information gathered during the
experiment.
Step 5 - Experimenting
To have a controlled
experiment, two groups must
be tested:
 Control Group- the group
where all the variables remain
constant
 the "normal group”
 Experimental Group- the group
exposed to the experimental
factor (independent variable –
what is being tested), but is
otherwise IDENTICAL to the
control group.
Step 5 - Experimenting
All factors in the control group and the
experimental group are identical except for
one:
 INDEPENDENT VARIABLE (input)
• what is being tested
During the experiment, observations and
measurements are taken from both groups,
looking specifically at another factor or
variable:
 DEPENEDENT VARIABLE (output)
– dependent because it is driven by/or results from the
effect of the independent variable.
~ FYI ~
For example, if we were setting up an
experiment to test our hypothesis about
“Tomato Grow” plant food, we would set
up the experiment using two groups of
identical tomato plants. One group, our experimental
group would receive the food, while the other group,
the control group would not. All other variables
would remain constant. The plant food would be
considered the independent variable, and only given
to the experimental group. In this case, the size of
the tomatoes would be the dependent variable, as
this factor is dependent upon the manipulation and
effect of the independent variable.
• What factors must remain the same in both
groups to ensure that the results you observe
are due to changes resulting from the variable
being tested ONLY?
~ FYI ~
If you said one or more of the following, you
are correct!
–Type and number of plants
–amount of water given
–the temperature of the environment
–amount of sunlight the plants receive
–The pH of the soil
–etc.
Control Group
pH 7
Experimental Group
pH 7
Step 5 - Experimenting
 Collecting & Organizing Data:
– Involves placing observations and
measurements (data) in order.
• Charts, tables, graphs or maps.
Step 5 - Experimenting
 Analyzing data
– Determine if the data has meaning
– Is the data reliable (trustworthy)?
• If Yes---run the experiment again…and again!
• If NO---make a new hypothesis and run experiment
again.
Step 6 – Conclusion &
Communication
A conclusion is a summary of the experiment's
results. The results are often represented in the
form of a model.
–
–
–
–
A MODEL is an explanation supported by data
It can be visual, verbal or mathematical
Should support the hypothesis
Should be re-testable
Step 6 – Conclusion &
Communication
A conclusion is sometimes drawn from an
Inference.
– made on the basis of premise and previous knowledge rather
than direct observations.
– It is still an explanation supported by data
– Unlike a Hypothesis, an inference is not directly testable…
Step 6 – Conclusion &
Communication
Scientists communicate the results of their
studies with other scientists (peers).
• Publish findings in journals
• Present their findings at
scientific meetings
Scientists must be unbiased
• Should not tamper with their
data
• Only publish & report
tested & proven ideas that can
be re-tested & produce the same
results.
Step 6 – Conclusion &
Communication
Hypothesis
Theory
Law
No hypothesis or explanation in science is ever
really final.
Science is an ongoing process which is
constantly revised and improved as new
evidence is found.
But many hypotheses have held up over time.
A Hypothesis that has ‘stood the test of time’
(even with minor revisions) may led to
Theories & Laws
Step 6 – Conclusion &
Communication
Forming a Theory
A theory may be formed after many hypotheses have
been tested and supported
– not speculation! What is thought to be true!
– supported by much evidence, data
– A comprehensive statement of an explanation of a
particular phenomenon
– CAN BE PROVEN WRONG!
Step 6 – Conclusion &
Communication
Hypothesis
Theory
Law
LAWS:
Theories are explanations of observations.
On the other hand, LAWS are statements about
events that always occur in nature.
A LAW doesn’t explain why something happens,
it just merely states that it does happen…
– Accepted to be true
– Universal
– Is usually expressed as a math equation
e.g. E=mc2
– Scientists use laws to explain theories…
The Scientific Method
TOOLS OF THE TRADE
Microscopes:
Sometimes we need to see things
smaller than we can see with our
eyes.
WHAT DOES A MICROSCOPE DO?
Produces a larger image of an object.
Uses a glass lens and a beam of light.
Magnification-the amount an object’s
size is increased
Resolution-the power to show details
clearly
Microscopes vary in powers of
magnification and resolution.
LIGHT MICROSCOPES
*Compound Light Microscope
•Specimen mounted on a
glass slide
•Must be thinly sliced or very
small
•Pair of lenses
o Ocular lens (eye piece)
o Objective lens (nose piece)
•Can be used to study LIVE
specimens
•Magnification determined by
multiplying power of both lenses
o Eyepiece 10X times Objective
power (10X, 20X, 40X…)
•Highest Maximum magnification is
around 1000X
LIGHT MICROSCOPES
ELECTRON MICROSCOPES
*Transmission Electron Microscope (TEM)
•Uses a beam of electrons to produce an
enlarged image of very thinly sliced specimen
on screen or photographic plate
•Image focused by magnetic lenses
•200,000X magnification
•Cannot be used to view living specimens
ELECTRON MICROSCOPES
*Scanning Electron Microscope (SEM)
•3D image
•Specimens not sliced for viewing
•Surface sprayed with fine metal coating
•Also uses electron beam and fluorescent
screen or photographic plates
•100,000X magnification
•Cannot be used to view living specimens
Tools of the trade
The International System of
Measurement, or SI is the one
system of measurements
scientists use.
Named after the French –
‘Systeme International d’Unites’
and formerly known as:
The Metric System
Tools of the trade
The Metric System
• Major advantages:
– It is a decimal system based on multiples or
fractions of 10’s
– Commonly used among all scientists
– Easy to convert between prefixes:
–
–
–
–
–
Kilo – 1000
Deci – 1/10th
Centi – 1/100th
Milli – 1/1,000th
Micro – 1/1,000,000th …of the base UNIT
Tools of the trade
The Metric System
– Uses Base Units • Describe what you are measuring.
»
»
»
»
»
Length-meter (m)
Volume-liter (L)
Mass-gram (kg)
Temperature-Celsius (C)
Time-second (s)
BASE UNIT
MEASURES
Meter
Length
Liter
Volume
Gram
Mass
TOOLS OF THE TRADE
PREFIX
…PLUS BASE UNIT
Kilo – 1/1000th
Kilo+gram =
Kilogram
Hecto – 1/100th
Hecto+liter =
hectoliter
Deka – 1/10th
Deka+gram =
dekagram
Deci - 10
Deci+liter =
deciliter
Centi - 100
Centi+meter =
centimeter
Milli - 1000
Milli+meter =
milliliter
In SI, prefixes are added to the
base unit (meter, gram, liter).
•The prefixes help us to
understand the amount more
easily
•Prefixes are multiples of 10…
•So 1 kilogram is 1000 X larger
than a gram or 1000 grams
•1 centimeter is 1/100th of a
meter or 100 X smaller than a
meter
•1 milliliter is 1/1000th of a
liter, or 1000 X smaller than a
liter
TOOLS OF THE TRADE
The SI System makes
conversions easier!
•1 mile=1760 yards=5280 feet= 63,360
inches – Ugh!!
•Because all of the unit relationships in
the metric system are based on multiples
of 10, it is easy to convert between prefix
units - just multiply or divide by 10!
•100,000 cm = 1000 meters = 1 kilometer
•1 kilometer = 1000 meters = 100,000 cm
Tools of the trade
For example:
• Centimeters are 10 times larger than
millimeters
So..
• 1 centimeter = 10 millimeters
Kilo-
Hecto-
.001
.01
Deka-
.10
BASE UNIT
Meter
Gram
liter
1
Deci-
10
Centi-
100
Milli-
1000
Tools of the trade
1 centimeter = 10 millimeters
40
1 mm
40
1 cm
41
1 mm
1 mm
1 mm
1 mm
1 mm
1 mm
1 mm
1 mm
1 mm
41
TOOLS OF THE TRADE
US Conversions within the
Metric
System
A QUICK SIDE NOTE…
Mass vs. Weight
(Not the same!)
Mass-How much matter (particles) you are
made of.
Weight-How much gravity pulls on you.