CHAPTER 1-A VIEW OF LIFE
I. BIOLOGY-the science that examines living organisms and all of the processes relating to living things.
A. Biology is a science. Science is defined as knowledge based on observed facts.
II. THE SCIENTIFIC METHOD-the process that allows a scientist to formulate and test scientific ideas.
A. Steps in The Scientific Method:
1. Identify the problem or question that you wish to answer. Biologists attempt to answer
a number of different questions. For example, they look at ways to treat and cure illnesses
as well as ways to protect and preserve our environment.
2. Develop hypotheses relating to your question.
a. Hypothesis-an educated guess. These serve as possible explanations for your
question. A hypothesis may or may not be correct.
b. Involves inductive reasoning-arriving at a conclusion based on one’s observations.
3. Experimentation-tests that are used to determine if your hypotheses are correct or not.
a. Experiments should be conducted on each of your hypotheses.
b. Experimentation is based on deductive reasoning-using information to draw a
conclusion about a specific case.
c. Variables-the specific factors that influence an experiment.
1) Independent variable-controlled by the person doing the experiment.
2) Dependent variable-observed result influenced by the independent variable.
d. Control-a version of the experiment in which everything is the same except for the
variable being examined. Controls are used as comparison experiments. Any observed
differences between the experiment and control should be an effect in changing the
variable you are observing.
e. From the experiments, you should determine if your hypotheses are correct or not.
If your hypotheses are incorrect, then you should develop new hypotheses.
f. Several experiments may be conducted to test a hypothesis.
g. Experiments produce results known as data.
4. Conclusions-should be developed from your experimentation. These conclusions should
relate to your hypotheses.
5. Publish your results in a scientific journal. This allows others to see what you have done.
Even if your hypotheses are proven wrong, you should still publish your results.
(Example of scientific study from text)
B. Scientific Theories-a hypothesis that is supported by a great deal of evidence. Theories have been
proven correct through repeated experimentation. Principles and Laws are theories that have become
accepted as the truth.
III. CHARACTERISTICS OF LIVING ORGANISMS
A. Living organisms are composed of small functioning units known as cells. Cells are the smallest living
pieces of matter. Living organisms can either be unicellular or multicellular.
B. Living organisms contain deoxyribonucleic acid (DNA). DNA functions as the primary hereditary
material for all living organisms.
C. Living organisms undergo a variety of different reactions.
1. Many of these reactions are involved in generating energy.
2. Metabolism-the total of all of the reactions that occur in a living organism. There are 2
major sets of reactions that occur in living organisms:
a. Anabolic reactions-reactions that build-up large molecules in an organism.
b. Catabolic reactions-reactions that breakdown large molecules into smaller molecules
in living organisms.
3. Adenosine triphosphate (ATP)-compound that serves as the major source of cellular
energy in living cells. Many of the reactions that occur in all living organisms are
involved in generating ATP.
D. Living organisms are adaptable-they can respond or adapt to internal and external changes in their
surroundings.
E. Living organisms can grow.
F. Living organisms can reproduce and develop.
G. Living organisms exhibit homeostasis.
1. Homeostasis-the ability of an organism to maintain a stable internal environment.
2. Homeostasis must be maintained for a living organism to function properly. Living
organisms have a variety of devices that allow them to maintain stability.
3 Stress-any condition that alters homeostasis. Disease is a major stress for living things.
IV. LEVELS OF ORGANIZATION IN LIVING ORGANISMS
A. Chemical Level of Organization-lowest level; includes atoms and molecules.
B. Cellular Level of Organization-includes cells.
C. Tissue Level of Organization-includes tissues. Tissues are groups of cells that work together to
carry out similar functions. Tissues are found in both plants and animals.
D. Organ Level of Organization-includes organs which are groups of tissues that work together to
carry out similar functions.
E. System Level of Organization-includes systems which are groups of organs that work together to
carry out similar functions.
F. Organismic Level of Organization-includes a living organism.
G. Population-group of individuals of the same species living in a certain area.
H. Community-all of the populations of all species living in a given area.
I. Ecosystem-a community interacting with its physical and chemical environment.
J. Biosphere-all area of the earth in which organisms live.
V. CLASSIFYING LIVING ORGANISMS
A. Taxonomy-the science of naming and classifying living organisms.
B. The Taxonomic Hierarchy-developed by Linneaus in the 1700’s.
1. Categories in the Taxonomic Hierarchy
a. Domain-most inclusive category
Kingdom
Phylum
Class
Order
Family
Genus
Species-least inclusive
category
2. Scientific Names=Genus name + Species Name
a. Binomial Nomenclature-
b. Rules for Writing Scientific Names
1) Capitalize the first letter of the Genus name.
2) The first letter of the Species name is not capitalized.
3) The entire Scientific Name should be underlined.
4) Example: Zea mays
3. Human Classification in the Taxonomic Hierarchy
4. Today, Taxonomists recognize 6 distinct Kingdoms:
a. Kingdom Archae
b. Kingdom Eubacteria
c. Kingdom Protista
d. Kingdom Fungi
e. Kingdom Plantae
f. Kingdom Animalia
5. There are millions of species of organisms that have been named and classified based
on the above system, however, there are millions of others that have not been seen by
biologists, so they have not been classified.
6. Criteria Used to Classify Living Organisms:
a. Cell type
b. Genetic make-up of the organism
c. Physical characteristics
d. How the organism obtains its food (mode of nutrition)
e. Overall complexity of the organism
VI. CHALLENGES FACING BIOLOGISTS
A. Biodiversity-total number and abundance of species in ecosystems. The death of a species (extinction)
is a challenge that a number of species are facing due to habitat loss.
B. Emerging Diseases-Avian Flu, Swine flu and Sever acute respiratory syndrome are “new” diseases
that appear in humans due to exposure to animals that act as vectors for the illness.
VII. FIELDS OF STUDY IN BIOLOGY
A. Anatomy-study of the structure of an organism.
B. Physiology-study of the functioning of an organism.
C. Cytology-the study of the structure and functions of cells.
D. Genetics-the study of hereditary relationships.
E. Evolution-the study of population changes that occur over time.
F. Ecology-the study of the relationships between organisms and their environment.
G. Botany-the study of plants.
H. Zoology-the study of animals.
I. Phycology-the study of algae.
J. Mycology-the study of fungi.
K. Bacteriology-the study of bacteria.
L. Virology-the study of viruses.