Biology: The Study of Life
Biology I – An Introduction
What is Biology?
• The scientific study
of living things
• from the Greek words
bios = life
&
-ology = the study of
Why Study Biology?
Understand the natural world
Learn to protect the environment
Develop skills for learning in your
future lives
Reject Myths that Explain
Biological Processes
• for example…
• Disease is caused by
evil spirits
• Your blood determines
your heredity
• Your heart carries your
emotions
How Does Science Separate
Myths from Reality?
Scientific
Method
Scientific Method
• Observation
• Hypothesis
– Prediction
• Test Hypothesis
– Experiment
– Further Observations
• Conclusion
• for example…
Edward Jenner 1749-1823
• Smallpox
– nasty disease which
killed millions
• Scientific Method
– technique he used to
find a vaccine for it
First Step: Observation
• Smallpox is deadly (30-40% mortality rate)
First Step: Observation
• But, those who survive the disease are immune
First Step: Observation
• In addition, milkmaids do not get smallpox…
First Step: Observation
• Milkmaids get cowpox from cows
Second Step: Hypothesis
•Jenner had an idea;
•Does Cowpox Makes You
Immune to Smallpox?
Third Step: Make a Prediction
• Prediction: If you are exposed to
cowpox, you will be immune to
smallpox
• This hypothesis and prediction is
based on Jenner’s
milkmaid/cowpox observations
Fourth Step: Experiment
Fourth Step: Experiment
• In 1796 Dr. Jenner tested his idea for a smallpox
vaccination on his gardener's son, an eight-year-old boy
named James Phipps.
• He got the term "vacca" from the Latin word for "cow.“
• The boy did get Cowpox, but recovered from it within a
few days. Jenner then waited eight weeks for the boy's
body to build an immunity.
• To complete his experiment, Jenner exposed James to
Smallpox. Amazingly, the boy did not contract the deadly
disease, and the doctor claimed success!
Fifth Step: Conclusion
• Since getting Cowpox seemed to prevent
anyone from getting Smallpox, Jenner had
confirmation of his original hypothesis
• His hypothesis was supported by his
experiments
Scientific Method
• Really, it’s just a formal breakdown of how
our minds work when we’re trying to solve
a problem.
• In life, we see a thing we don’t understand,
we question it, we think of an explanation
or idea, we test that explanation, and we
evaluate our test.
Time for a Break….
Biology I - Initial Concepts
• An overview:
1. Earth: Unity of Diversity
2. Evolution
3. Hierarchy of Organization
4. Emergent Properties
5. The Cellular Basis of Life
1. Earth: Unity of Diversity
• There are between 5 and 30 million
species of living things on the
earth.
• To date: ~1.5 million species have
been identified.
~ 1.25 million animals
~ 250,000 plants
1. Earth: Unity of Diversity
• To organize all of these
organisms, scientist classify
species into categories.
• Taxonomy: the naming and
classifying of organisms.
1. Earth: Unity of Diversity
• Taxonomic groups are ranked into a hierarchy
from MOST to LEAST INCLUSIVE.
1.
2.
3.
4.
5.
6.
7.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Carnivora
Canidae
Canus
lupus
the animals
backbones
warm blooded
eat meat
canine family
dog genus
wolves
1. Earth: Unity of Diversity
• There are 6 Kingdoms of life:
1. Monera: bacteria
2. Archaebacteria: weird microbes
3. Protista: single celled animals
4. Plantae: plants
5. Fungi:
yeast & molds
6. Animalia: animals
2. Evolution
• Life evolves & species change over
time.
• Evolution is a change in the genes
(DNA)
• All life is connected and can be traced
back ~3.5 billion years on Earth.
• Evolution is the one biological theme
that ties all together.
2. Evolution
• Charles Darwin proposed Natural
Selection in his book:
“On the Origin of Species by Means of
Natural Selection”
• Natural Selection:
Environmental factors that favor
the reproductive success of some
individuals over others.
3. Hierarchy of Organization
• Biological organization: Based on structural
levels from Least to Most Inclusive.
1. Atoms
2. Molecules
3. Organelles
4. Cells
5. Tissues
6. Organs
7. Organ systems
3. Hierarchy of Organization
8. Organisms:
species
9. Populations: localized groups of organisms
belonging to the same species.
10. Community: populations of species living
in the same area.
11. Ecosystem: community interactions
12. Biomes:
large scale communities
13. Biosphere: the sum of all earth’s
ecosystems.
4. Emergent Properties
(what is life...)
A. Complexity
B. Reproduction
C. Growth and development
D. Transform energy to Food
E. Respond to stimuli
F. Adapts to the environment
5. The Cellular Basis of Life
• Cells are the lowest level of structure capable
of all activities of life.
• Cell Doctrine/Theory: 1852 by Robert Hooke.
A. Cells are the basic unit of life.
B. Cells arise from pre-existing cells (mitosis).
C. Cells are surrounded by a membrane.
D. Cells transform energy (cellular respiration).
E. Cells have information retention and transfer in
the form of genes (DNA - pass to offspring).
The End…