INTRODUCTION



     Evolution is more than simply one of the specialized topics 
which constitutes the subject matter of biology and which is 
taught as a separate course of study in a college curriculum.  
Since the 1960s evolution has become one of the dominant themes 
which organizes all the facts of biology and almost all modern 
textbooks of general biology use the concept of evolution as their 
overriding theme.  The reason is that biology deals with diversity 
at all levels of study from macromolecules to ecosystems and the 
process behind the production of biological diversity is 
evolution.


     On the other hand all living things have a common structural 
base - they are all composed of cells and use nucleic acids, e.g., 
DNA, as their hereditary material.  This structural commonality 
also serves to unify biology and the statement of this unity is 
the cell theory: all organisms are composed of cells and all cells 
come from pre-existing cells.  If this is so, why are cells and 
organisms so diverse?  The answer is evolution: descent with 
modification during the long history of cellular lineage.  Thus, 
modern biology has two major unifying themes:  the cell theory 
which accounts for the structural integrity of living forms and 
their continuity over time, and the theory of evolution which 
explains organic diversity.  Both of these theories, formulated in 
the middle of the 19th Century, are considered to be facts by the 
scientific community and are essentially inductive 
generalizations, i.e., based on a limited number of observations.  
Nobody has observed all living things or the entire history of 
life (phylogeny), hence these two theories are based on the 
observations that (1) all things known to be alive and so 
constitute the subject matter of biology are composed of cells, 
(2) all cells and individuals studied today come from parents via 
the process of reproduction, and (3) variation within and among 
species is sequential over space and time.


     The mechanism or process which accounts for the cell theory 
(reproduction) is well understood because it can be observed 
today; but the process behind evolution is highly controversial 
since it operates over a time dimension so vast that it cannot be 
directly observed.  Biologists have observed the phenomenon and 
mechanism of cell continuity but they have not observed the 
transformation of one species into another.  For this reason the 
study of evolution is fascinating, subject to much debate within 
the scientific community, and loaded with implications for our 
view of humanity which has been developed up to now through a 
nonevolutionary perspective.



             The Organization of This Course


     Consider the following question:  WHAT WAS THE WORLD LIKE IN 
THE PAST?


     Now consider a number of possible answers.


     1.  WHO CARES?  At first glance this answer seems unworthy of 
anyone who possesses even a minimal sense of curiosity and would 
be expected from someone who will never benefit from a college 
education.  But on further reflection this answer might be quite 
appropriate.  The purpose of a college education is to provide the 
knowledge and skills needed to be successful in our complex modern 
environment and so what happened in the past is irrelevant to our 
understanding of today's world.  This attitude is reflected in the 
next two possible answers which provide reasons why a knowledge of 
the past is irrelevant.


     2.  THE QUESTION IS MEANINGLESS BECAUSE WE CANNOT KNOW WHAT 
HAPPENED IN THE PAST.  This answer points to an epistemological 
problem, namely, how can we study the distant past?  We can learn 
about the recent past from eye witness accounts of other humans 
revealed in historical documents.  Historical documentation based 
on human witness, however, can only take us back about 15.000 
years if we include cave drawings as part of the historical 
record.  What happened before that is unknowable.  Some would 
argue that the world isn't even that old and at most is about six 
thousand years old.


     3.  THE QUESTION IS ANSWERABLE BUT THE ANSWER IS OF NO VALUE.  
This answer suggests that the present either does not build on the 
past or that, if it does, the processes which shaped past events 
were unique and will not be repeated.  Hence, an understanding of 
the past will provide no insight into the way the world operates 
today.


     4.  THE ANSWER IS IMPORTANT BECAUSE THE WORLD OF THE PAST IS 
ESSENTIALLY THE SAME AS THE WORLD OF TODAY.  This answer reflects 
the idea that history is cyclical and so an understanding of the 
past will enable us to avoid making the same mistakes our 
forebears made.  This view of the world also suggests that the 
world is static and change is unimportant because whatever change 
does occur is not progressive.


     5.  THE ANSWER IS IMPORTANT BECAUSE THE PRESENT IS THE 
PRODUCT OF THE PAST AND SO THE FUTURE WILL BE SHAPED BY WHAT 
HAPPENS IN THE PRESENT.  This view suggests that the world is 
dynamic and change is progressive.  A study of the past will 
reveal how the world actually operates and armed with this 
information we can confidently plan for the future.


     This course will provide you with a basis for answering this 
question and for deciding which of the above answers is 
essentially correct.  It will then be up to you to decide how you 
should order your life based on this knowledge.



     Your syllabus will serve as a guide to the way we will answer 
the question posed above.  The starting point will be to examine 
two contrasting views of the world: the world of creation based on 
a static worldview and the world of evolution based on a dynamic 
worldview.  Since the latter view is proper to the field of 
science, we will then examine the nature of science as a mode of 
inquiry and how historical subjects can be studied scientifically.  


     Since science deals with theories, we will then explore 
evolution as a scientific theory and examine the logical 
deductions which flow from this theory.  These deductions 
constitute the so-called evidences for evolution which you will be 
asked to evaluate as regards their bearing on the fact of 
evolution.


     The next step in the course will be to examine the various 
components of modern evolutionary theory, which is not a single 
theory but rather a composite of a number of specific theories all 
of which contribute to explaining the phenomenon of evolution.  
Among these specific theories are:

Mendel's theory of heredity, the theory of population genetics, 
the theory of genetic drift, Darwin's theory of natural selection, 
other theories of selection (kin and group selection), the theory 
of allopatric speciation and the macroevolutionary theories of 
gradualism and punctuationalism.


     Having completed this journey through modern evolutionary 
theory, we will then examine our own species as the product of 
evolutionary process and how an evolutionary or dynamic worldview 
impacts on our uniqueness as a species, our nature, and the 
nonscientific realms of ethics and religion.


     We will conclude the course by discussing our impact on the 
environment and how this relates to the difference between dynamic 
and static perspectives of how the world operates.  At this point 
you should be able to accept and defend one of the five possible 
answers given to the question posed above.


           Extension of the Concept of Evolution


     Evolution is, strictly speaking, a biological concept.  The 
term "evolution", however, is frequently applied beyond the field 
of biology and takes on the aura of an all-transforming principle 
of matter.  In this larger sense 

we can speak of inorganic or chemical evolution studied in 
cosmology at one end of the spectrum and of cultural or 
psychosocial evolution, unique to our own species, at the other 
end.  Biological or organic evolution occupies the middle position 
and is believed to have originated with the origin of life (viewed 
as a result of chemical evolution) and to have given rise to 
cultural evolution (with the evolution of humans).  The appended 
table (modified after Julian Huxley) contrasts these different 
arenas of evolution.


     This course is limited to the subject of biological evolution 
and so throughout the course I will make reference to organic 
diversity as a synonym for species diversity to reinforce this 
point.  The dynamic worldview described in this course, however, 
is bolstered by the extension of evolutionary thought to the 
worlds of nonliving matter and culture.