Chapter One:
Science as a Process
Ch. 1.1
Intro to Biology &
Characteristics of Life
SCIENCE
• The continuous effort to discover and
increase human knowledge through
research
• The process of observing, explaining,
and understanding our world
• Does NOT include “supernatural”
explanations
Biology
• “Bio” = life
“ology” = study of
• The study of life (organisms)
• Answers questions about the natural
world:
– How they work
– How they interact with the environment
– How they change over time
Branches of Biology
1. Anatomy: external &
internal structures of
organisms
2. Ecology: interactions
between organisms and
their environment
3. Cytology: structure &
function of cells
4. Botany: plants
5. Genetics: heredity, how traits pass
from parent to offspring
6. Microbiology: “micro” = small,
organisms seen with a
microscope
7. Taxonomy: classification
8. Zoology: animals
Characteristics of Life:
1.
2.
3.
4.
5.
6.
7.
Made of cells
Respond to stimuli (change in enviro.)
Maintain homeostasis
Use energy (metabolism)
Grow and develop
Reproduce
Change through time (evolution)
Homeostasis
• Stable internal conditions
• Ex:
– Temperature
• Ex: Thermostat
– Water intake
– Food intake
– pH
Metabolism
• Sum of all chemical rxns that take
in & transform E & materials from
the environment
• Photosynthesis: converts light E
into chemical E
• Cellular Respiration: converts
organic cmpds into usable E
(ATP)
Maple vs. robot toy
Themes in Biology
&
The Scientific Method
Ch. 1.2
Themes in Biology
1. Diversity and Unity of Life
2. Interdependence of Organisms
3. Evolution of Life
1. Diversity and Unity of Life
• Diversity = variety of life
– Cell = basic unit of life
– Highly organized
– Unicellular vs. Multicellular
– Cell differentiation- cells become
specialized
Solution #2
cell specialization and division of labor
cell specialization
elaboration of one function and reduction
of others
• Unity= all living things have features
in common
– The genetic code; the heredity info. in
DNA
– Contain organelles; cellular structures
that carry out specific functions
– “Tree of Life”; has 3 main branches
called domains and 6 major categories
called kingdoms
“Tree of Life”
2. Interdependence of Organisms
• Organisms interact with each
other and the living world
– Area of science known as Ecology
– Ecosystems are communities of
living species & their physical
environment
1. Can you name some parts of an ecosystem?
2. How have humans affected the environment?
3. Evolution of Life
• Populations of living organisms
change over time
• Descent with modification
• Occurs by natural selection;
organisms with more favorable
traits survive a changing
environment and reproduce more
successfully.
• Adaptations are traits that
improve an organisms chance of
survival.
Ch.1.3
The Scientific Method
• How problems are solved!
– Scientists use controlled methods to
collect observable evidence to
answer questions about natural
phenomena
– YouTube - Scientific Method MTV
Steps of the Scientific Method
1. Define the problem.
2. Collect information.
Qualitative vs. quantitative
3. Form a hypothesis.
– a statement that can explain a
scientists observations and data
– Must be testable
– Educated guess that can be proven
FALSE
– Written as an “if-than” statement
4. Test the hypothesis.
– Controlled experiments test variables by
comparing a control group with an
experimental group.
– The independent (manipulated) variable is
the one that is changed by the scientist
– The dependent (responding) variable
changes in response to the change made to
the ind. variable
Hypothesis Examples
• If skin cancer is related to ultraviolet light ,
then people with a high exposure to uv light
will have a higher frequency of skin cancer.
• If leaf color change is related to temperature ,
then exposing plants to low temperatures will
result in changes in leaf color.
• In the statements above the dependent variable is
blue and the independent variable is red.
5. Observe & record data.
6. Draw conclusions.
–
–
Support or refute hypothesis
A theory may be formed- a collection of ideas,
hypotheses, laws, and predictions which have
been successfully tested, but are subject to
modification when facts or experiments
demand it.
7. Report research methods & findings.
–
–
Scientific journals
Lab reports
Setting Up a Controlled Experiment
http://www.youtube.com/watch?v=GKGtkz
gKfkc&feature=related
Presenting Scientific Findings
• Tables- used to organize data
Graphs are used to visually represent
data
 Bar graphs- illustrate comparisons
 Line graphs- recognize patterns or trends
 Pie graphs- represent percentages
 Title of graph should include dependent
and independent variables
 Y-axis has the dependent variable
 X-axis has the independent variable
Microscopes
Light Compound Microscope (LM):
• used to see small organisms
and cells
• transparent specimen is
mounted on glass slide
• Light passes through the
specimen
(pg. 21, parts of the microscope)
Electron Microscopes
-
Use a beam of electrons
to produce an enlarged
image of a specimen
1) Transmission electron
microscope (TEM)• electrons sent through a
thin specimen
• cannot view living
specimens
• 200,000 x magnification
2) Scanning electron microscope (SEM)
• electrons pass over specimen
producing a 3D image
• 100,000 x magnification
• cannot view living organisms
Units of Measurement
• Scientists use one system of
measurement, the metric system
( SI system)
• Decimal system based on powers of 10
• SI has 7 base units