BIOL 1020 - CHAPTER 1 LECTURE NOTES
Chapter 1: Introduction – Themes in the study of life
I. Biology is Studied Using the Scientific Method
A. Science is based on a systematic thought process.
1. Deductive reasoning - Summarize the information at hand and draw conclusions from that
information; proceeds from the general to the specific.
2. Inductive reasoning - Drawing a generalization from several specific observations; proceeds from
the specific to the general. Must be careful, because it is impossible to prove the accuracy of the
B. Observations, testable models, and experiments
1. The scientific method is a recursive process for discovering knowledge that involves making
observations, making testable models, and conducting experiments.
2. First step involves collecting information and/or summarizing existing observations about the
phenomenon under study.
3. This permits the formulation of a hypothesis, a testable model that explains the existing
observations and makes predictions that can be tested.
4. An experiment is conducted to test the correctness of the hypothesis
• Experimental or treatment group - the individuals given the specific treatment or condition
• Control group - the individuals not given the specific treatment
5. Observation and measurement of the experimental and control groups and comparison of the data
obtained provides evidence to either support or reject the hypothesis.
6. Care must be taken that the experimental and control groups receive the same treatments except for
the specific effect being tested. Example: the placebo effect.
7. The recursive nature of the process: experiments provide more observations, and at any time more
observations may be added in and more testable models may be produced; this may in turn lead to
more experiments, and the process continues. This generally leads to progress towards more and
more reliable models of how nature works. Creative thinking often plays a major role when rapid
C. Hypothesis, theory, and law
1. A well supported hypothesis that links together a large body of observations is considered a theory.
2. A theory that links together significant bodies of thought and yields unvarying and uniform
predictions over a long period of time becomes considered a principle or law.
D. The supernatural, by definition, is outside the bounds of science. Supernatural causes and effects cannot
be proved or disproved.
E. science and technology – the goal of science is to understand nature; the goal of technology is to apply
scientific knowledge for a specific purpose
II. Characteristics of Living Matter
A. Living things are composed of cells.
1. Cell - The basic structural and functional unit of life consisting of living material bounded by a
membrane. The smallest unit of living things capable of growth and development.
2. Unicellular - An organism consisting of a single cell.
3. Multicellular - An organism consisting of more than one cell.
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B. Living things grow and develop.
1. Growth-increase in size because number of cells or size of cells increases.
2. Development-changes in roles of cells during the life cycle of an organism.
C. Metabolism includes the chemical processes essential to growth and repair.
1. Metabolism - the sum of the chemical reactions and energy transformations that take place within a
2. Homeostasis - the tendency of an organism to maintain a relatively constant internal environment.
D. Living things respond to stimuli (stimulus - physical or chemical changes in the internal or external
environment of an organism)
E. Living things reproduce.
1. Asexual reproduction – copying; reproduction not involving sex (genetic recombination); resulting
from only cell division.
2. Sexual reproduction – reproduction involving sex; typically involves the formation of specialized
egg and sperm cells and their fusion to produce a zygote which grows and develops into a new
III.Information Transfer in Living Systems
A. Information must be transferred from one generation to the next.
1. DNA (deoxyribonucleic acid) is responsible for information transfer from one generation to the next.
2. DNA is the chemical substance that makes up genes, the units of heredity.
B. Information must be transferred from one cell generation to the next.
C. Information is exchanged between cells.
1. Hormones are chemical signals used for intercellular signaling.
2. Physical signals also lead to intercellular communication, e.g. ne