Chapter 1
Biology, Scientific Process, and Tools
Objectives
Apply the Scientific Method to Solve a problem.
List the Characteristics of Living Things
Compare a Hypothesis and a Theory
INTERACTIVE
Quickwrite:
In your own words, What
is Biology?
Biology
The Study of LIFE
INTERACTIVE
• What makes something alive???
• Think, discuss, pass the pen
Characteristics of Life
• Biologists have established that all living
things share 7 Characteristics of Life.
Cells
Stimulus
Homeostasis
Metabolism
Growth and
Development
Reproduction
Change
through Time
Organization and Cells
• All living organisms (one celled or multicellular)
have some degree of organization.
• CELL—smallest unit of life
• UNICELLULAR—one celled organisms
• MULTICELLULAR—made up of more than one cell
• Complex Multicellular organisms (such as
humans) have ORGAN SYSTEMS, groups of parts
that carry out specific functions.
• ORGANS are structures that carry out specialized
jobs within an organ system.
Organization and Cells
• All organs are made up of TISSUES, or groups of
cells with similar functions.
• Tissues are made up of CELLS.
• ORGANELLES are within each cell and are tiny
structures that carry out functions necessary for
the cell to stay alive.
• Organelles contain BIOLOGICAL MOLECULES, the
chemical compounds that provide physical
structure, movement, energy.
• Biological Molecules are made up of ATOMS, the
simplest particle of an element.
Organism
Organ
Systems
Organs
Tissues
Organelles
Biological
Molecules
Atoms
Response to Stimuli
• An organism can respond to a STIMULUS or
physical/chemical change in the internal or
external environment.
• Example—an owl dilates its pupils to keep the
amount of light entering the eye constant and
therefore maintain good vision.
Homeostasis
• The maintenance of a stable level of internal
conditions even though the environment is
changing.
• Examples: Maintaining body temperature,
water content, nutrients within a cell
INTERACTIVE
• Prove it has the first 3 characteristics of life…
• Copy and complete the table:
Characteristic of Life
Cells and Organization
Stimulus
Homeostasis
Organism
Proof
Metabolism
• Living organisms use ENERGY to repair, move, and
grow.
• Metabolism is the sum of all the chemical reactions
that take in and transform energy and materials
from the environment.
• Example—plants use the sun’s energy to generate
sugar molecules through photosynthesis.
• Example—an owl’s metabolism allows the owl to
extract chemicals in its prey and use it as energy to
fuel growth.
Growth and Development
• All living things grow and increase in size.
• Living things grow from the results of divisions
and enlargements of cells.
• Unicellular—enlargement of cells
• Multicellular—division of cells
• Development is the process by which an
organism becomes a mature adult.
Reproduction
• All living organisms produce new organisms in a
process called reproduction.
• Reproduction (unlike the other characteristics is
NOT essential for life of a single organism, however
it is essential for the continuity of the species)
• During reproduction organisms transmit hereditary
info to their offspring. This info is encoded in DNA
(deoxyribonucleic acid).
• A short segment of DNA contains instructions for a
single trait (like eyecolor), this is called a GENE.
Reproduction
Sexual Reproduction
Asexual Reproduction
• Hereditary info
recombines from 2
organisms of the same
species.
• Results in similar (but
not identical to
parents) offspring.
• Hereditary info is not
recombined
• The offspring and the
original organism are
essentially the same
(genetically)
• Example—a bacterium
reproduces when it
splits into two identical
cells.
Change through Time
• Basic genetics do not change through time
• Populations of living organisms evolve or change
through time to survive
• Succession—the process by which a biological
community evolves over time
– Primary Succession—a lifeless area has to evolve
(example after a lava flow)
– Secondary Succession—a community is removed (but
not entirely, some life, soil remains) and begins again
(extinction of a species, weather related disasters)
Song—Characteristics of Living Things
• Which characteristic is missing??
INTERACTIVE
• Is it alive?
• Martian and the Car
Characteristics of Living Things
• Complete the graphic organizer and put it in
your notebook.
Science as a Process
• Science is characterized by an organized
approach…the SCIENTIFIC METHOD.
• Quickwrite…What do you know/remember
about the Scientific Method??
Scientific Method
Observation/
Question
Hypothesis
Experiment
Data/Results
Conclusion
Observations
• Science starts with observation
– Observation involves using the 5 senses to gather
information
– Can be quantitative (numbers) or qualitative (not
numerical, more descriptive)
– All of this information is gathered as DATA, or
evidence
– What are the 5 senses??
Interpreting the Evidence
• Scientists must make inferences based on the
observations.
• Inferences are a logical, unbiased,
interpretation based on prior knowledge,
experience, and observation
• Examples of Inferences:
– You see a broken window and a baseball laying on
the floor under the window. You INFER that the
baseball broke the window.
INFERENCE - a logical interpretation
based on prior knowledge
* Drawing a conclusion
Explaining the Evidence
• A HYPOTHESIS is a possible explanation or answer
to a scientific question.
• A Hypothesis must be TESTABLE.
• Examples:
1. Purina food will reduce a dog's shedding.
2. Putting Miracle Grow on tomato plants will make them produce more
tomatoes.
3. The drug Avapro will lower a person's blood pressure.
Examples of Hypotheses
Good
Plants will grow taller
with Miracle Grow.
Bad
Examples
Plants will grow better
when given Miracle
Grow.
Girls will score higher Girls are smarter than
on math tests than
boys.
boys.
Hermit crabs will
Hermit crabs like
choose colorful shells colorful shells.
over plain shells.
INTERACTIVE
• Write a hypothesis for the experiment below:
– A scientist is going to measure toy car speed on a
ramp. He is going to test if the size of the wheel
affects the speed of the toy car going down a
ramp. He has a regular toy car, a toy car with
extra large wheels, and a toy car with mini-wheels.
– What is your hypothesis??
Identify the GOOD hypotheses
Copy the good hypotheses and explain why it is
good.
• Plants will grow taller with sunlight.
• Boys like video games.
• 9th graders are better than middle school
students.
• Dogs will run faster after eating a bone.
• Bounty paper towels can hold more water
than the store brand.
• Cats are good mouse hunters.
Setting up a Controlled Experiment
• A controlled experiment is a test of a hypothesis
with only one variable being tested.
• Manipulated (Independent) Variable is the part of
the experiment that is being deliberately changed
by the scientist.
• Responding (Dependent) Variable is the part of
the experiment that that changes as a result of
the experiment.
• Controlled Variables: items that stay constant
throughout the experiment (example: the
materials used)
INTERACTIVE
A scientist is going to measure plant growth under
different colors of light. He is going to expose the same
type of plants to yellow, green, blue light, and sunlight.
What would your hypothesis be??
What would the Manipulated/Independent
Variable be??
What would the Responding/Dependent
Variable be??
Recording and Analyzing Results
• Scientist keep written records of all
observations and data, often in a journal,
notebook, or computer.
• Statistical Variability– how spread out the
group of data is. Data sets with very similar
numbers have little variability. Data sets with
a wide range would be highly variable.
Error
• No experiment is perfect. Many things can go
wrong and many things cannot be controlled.
• Scientists acknowledge that there will be error.
• Scientists ALWAYS identify and communicate
sources for error.
Sources for Error…
Human Error
Instrument
Error
Environmental
Materials not
uniform
Drawing a Conclusion
• Scientists then use the data and results from an
experiment to evaluate the original hypothesis and
develop a conclusion.
• Scientists will answer their original questions,
confirm or reject their hypothesis, and often create
new questions
Publishing
• If evidence supporting a hypothesis builds up
from many, many experiments by many
scientists, the hypothesis becomes a THEORY.
• A THEORY is a well-tested explanation or
answer to a problem.
Hypothesis vs. Theory
Hypothesis
•Educated guess
•Not tested yet
or
•Not tested
much
Theory
•Well-accepted
answer
•Well-tested
•Supported by
many
experiments
Mythbusters and the Scientific Process
Mythbusters Episode: Identifying the Steps of the
Scientific Method and possible sources of Error!
1.Watch the episode of Mythbusters.
2.While watching, fill in the steps of the Scientific
Method and the possible sources of error.
3.Create a Mini-Board
Scientific Method in Action!
Honors:
Penny Lab!
Med Bio:
Science and Medicine!
Tools and Techniques
Light Microscope
• To see small organisms and cells scientists
usually use LIGHT MIRCROSCOPES.
• A compound light microscope has 2 lenses to
magnify an image.
• 4 major parts to a light microscope:
– Eyepiece
– Objective lens
– Stage
– Light Source
Magnification and Resolution
• Magnification– The increase in the objects
apparent size
• Example: 10x means 10 times the objects real
size.
• Resolution: the power to show details clearly
(how focused it is)
Electron Microscope
• To examine cells in great detail or study cell
parts or viruses, scientists use Electron
Microscopes.
• Very powerful magnification and resolution.
• Always in black and white (computers can add
color)
Microscope Lab
Metric System
• Scientists use a common measuring system so
they can compare and understand results.
• Called SI or Metric System
• Metrics Lab!
Vocabulary
Create a flash card for
the following terms:
1.
2.
3.
4.
5.
6.
Biology
Cell
Tissues
Organelle
Biological molecule
Scientific Method
7. Hypothesis
8. Theory
9. Control
10.Independent Variable
11.Dependent Variable
12.Observation
13.Compound Light
Microscope
14.Metric System