Theories explaining biological evolution have been bandied
about since the ancient Greeks, but it was not until the
Enlightenment of the 18th century that widespread
acceptance and development of this theory emerged. In the
mid 19th Century, English naturalist Charles Darwin - who
has been called the "father of evolution" - conceived of
the most comprehensive findings about organic evolution
ever. Today many of his principles still entail modern
interpretation of evolution. 
Darwin's findings marked a revolution of thought and social
upheaval unprecedented in Western consciousness challenging
not only the scientific community, but the prominent
religious institution as well. Another revolution in
science of a lesser nature was also spawned by Darwin,
namely the remarkable simplicity with which his major work,
"The Origin of the Species" was written - straightforward
English, anyone capable of a logical argument could follow
it - also unprecedented in the scientific community
(compare this to Isaac Newton's horribly complex work
taking the scientific community years to interpret).
Modern conception of species and the idea of organic
evolution had been part of Western consciousness since the
mid-17th Century (a la John Ray), but wide-range acceptance
of this idea, beyond the bounds of the scientific
community, did not arise until Darwin published his
findings in 1958. Darwin first developed his theory of
biological evolution in 1938, following his five-year
circumglobal voyage in the southern tropics (as a
naturalist) on the H.M.S. Beagle, and perusal of one Thomas
Malthus, "An Essay on the Principle of Population", which
proposed that environmental factors, such as famine and
disease limited human population growth. This had direct
bearing on Darwin's theory of natural selection, furnishing
him with an enhanced conceptualization of the "survival of
the fittest" - the competition among individuals of the
same species for limited resources - the "missing piece" to
his puzzle. For fear of contradicting his father's beliefs,
Darwin did not publish his findings until he was virtually
forced after Alfred Wallace sent him a short paper almost
identical to his own extensive works on the theory of
evolution. The two men presented a joint paper to the
Linnaean Society in 1958 - Darwin published a much larger
work ("a mere abstract of my material") Origin of the
Species a year later, a source of undue controversy and
opposition (from pious Christians), but remarkable
development for evolutionary theory. 

Their findings basically stated that populations of
organisms and individuals of a species were varied: some
individuals were more capable of obtaining mates, food and
other means of sustenance, consequently producing more
offspring than less capable individuals. Their offspring
would retain some of these characteristics, hence a
disproportionate representation of successive individuals
in future generations. Therefore future generations would
tend to have those characteristics of more accommodating
individuals. This is the basis of Darwin's theory of
natural selection: those individuals incapable of adapting
to change are eliminated in future generations, "selected
against". Darwin observed that animals tended to produce
more offsprings than were necessary to replace themselves,
leading to the logical conclusion that eventually the earth
would no longer be able to support an expanding population.
As a result of increasing population however, war, famine
and pestilence also increase proportionately, generally
maintaining comparatively stable population.
Twelve years later, Darwin published a two-volume work
entitled "The Descent of Man", applying his basic theory to
like- comparison between the evolutionary nature of man and
animals and how this related to socio-political development
man and his perception of life. "It is through the blind
and aimless progress of natural selection that man has
advanced to his present level in love, memory, attention,
curiosity, imitation, reason, etc. as well as in knowledge
of morals and religion". 

Here is where originated the classic idea of the evolution
of man from ape, specifically where he contended that
Africa was the cradle of civilization. This work also met
with opposition but because of the impact of his
"revolutionary" initial work this opposition was
comparatively muted.
A summary of the critical issues of Darwin's theory might
be abridged into six concise point as follows:
1 Variation among individuals of a species does not
indicate deficient copies of an ideal prototype as
suggested by the platonic notion of Eidos. The reverse is
true: variation is integral to the evolutionary process.
2 The fundamental struggle in nature occurs within single
species population to obtain food, interbreed, and resist
predation. The struggle between different species (i.e..
fox vs. hare) is less consequential.
3 The only variations pertinent to evolution are those
which are inherited.
4 Evolution is an ongoing process which must span many
moons to become detectably apparent.
5 Complexity of a species may not necessarily increase with
the evolutionary process - it may not change at all, even
6 Predator and prey have no underlying purpose for
maintenance of any type of balance - natural selection is
opportunistic and irregular.
The scientific range of biological evolution is remarkably
vast and can be used to explain numerous observations
within the field of biology. Generally, observation of any
physical, behavioral, or chemical change (adaptation) over
time owing directly to considerable diversity of organisms
can be attributed to biological evolution of species. It
might also explain the location (distribution) of species
throughout the planet.
Naturalists can hypothesize that if organisms are evolving
through time, then current species will differ considerably
from their extinct ancestors. The theory of biological
evolution brought about the idea for a record of the
progressive changes an early, extinct species underwent.
Through use of this fossil record paleontologists are able
to classify species according to their similarity to
ancestral predecessors, and thereby determine which species
might be related to one another. Determination of the age
of each fossil will concurrently indicate the rate of
evolution, as well as precisely which ancestors preceded
one another and consequently which characteristics are
retained or selected against. Generally this holds true:
probable ancestors do occur earlier in the fossil record,
prokaryotes precede eukaryotes in the fossil record. There
are however, significant "missing links" throughout the
fossil record resulting from species that were, perhaps,
never fossilized - nevertheless it is relatively compatible
with the theory of evolution.
It can be postulated that organisms evolving from the same
ancestor will tend to have similar structural
characteristics. New species will have modified versions of
preexisting structures as per their respective habitats
(environmental situations). Certainly these varying species
will demonstrate clear differentiation in important
structural functions, however an underlying similarity will
be noted in all. In this case the similarity is said to be
homologous, that is, structure origin is identical for all
descended species, but very different in appearance. This
can be exemplified in the pectoral appendages of
terrestrial vertebrates: Initial impression would be that
of disparate structure, however in all such vertebrates
four distinct structural regions have been defined: the
region nearest the body (humerus connecting to the pectoral
girdle, the middle region (two bones, radius and ulna are
present), a third region - the "hand" - of several bones
(carpal and metacarpal, and region of digits or "fingers".
Current species might also exhibit similar organ functions,
but are not descended from the same ancestor and therefore
different in structure. Such organisms are said to be
analogous and can be exemplified in tetrapods, many
containing similar muscles but not necessarily originating
from the same ancestor. These two anatomical likenesses
cannot be explained without considerable understanding of
the theory of organic evolution.
The embryology, or early development of species evolved
from the same ancestor would also be expected to be
congruent. Related species all share embryonic features.
This has helped in determining reasons why development
takes place indirectly, structures appearing in embryonic
stage serve no purpose, and why they are absent in adults.
All vertebrates develop a notchord, gill slits (greatly
modified during the embryonic cycle) and a tail during
early embryology, subsequently passing through stages in
which they resemble larval amphioxus, then larval fishes.
The notchord will only be retained as discs, while only the
ear canal will remain of the gills in adults. Toothless
Baleen whales will temporarily develop teeth and hair
during early embryology leading to the conclusion that
their ancestors had these anatomical intricacies. A similar
pattern, exists in almost all animal organisms during the
embryonic stage for numerous formations of common organs
including the lungs and liver. Yet there is a virtually
unlimited variation of anatomical properties among adult
organisms. This variation can only be attributed to
evolutionary theory.
Biological evolution theory insists that in the case of a
common ancestor, all species should be similar on a
molecular level. Despite the tremendous diversity in
structure, behaviour and physiology of organisms, there is
among them a considerable amount of molecular consistency.
Many statements have already been made to ascertain this:
All cells are comprised of the same elemental organic
compounds, namely proteins, lipid and carbohydrates. All
organic reactions involve the action of enzymes. Proteins
are synthesized in all cells from 20 known amino acids. In
all cells, carbohydrate molecules are derivatives of
six-carbon sugars (and their polymers). Glycolysis is used
by all cells to obtain energy through the breakdown of
compounds. Metabolism for all cells as well as
determination of definitude of proteins through
intermediate compounds is governed by DNA. The structure
for all vital lipids, proteins, some important co-enzymes
and specialized molecules such as DNA, RNA and ATP are
common to all organisms.
All organisms are anatomically constructed through function
of the genetic code. All of these biochemical similarities
can be predicted by the theory of biological evolution but,
of course some molecular differentiation can occur. What
might appear as minor differentiation (perhaps the
occurrence-frequency of a single enzyme) might throw
species into entirely different orders of mammals (i.e..
cite the chimpanzee and horse, the differentiation
resulting from the presence of an extra 11 cytochrome c
respiratory enzymes). Experts have therefore theorized that
all life evolve from a single organism, the changes having
occurred in each lineage, derived in concert from a common
Breeders had long known the value of protective resemblance
long before Darwin or any other biological evolution
theorists made their mark. Nevertheless, evolutionary
theory can predict and explain the process by which
offspring of two somewhat different parents of the same
species will inherit the traits of both - or rather how to
insure that the offspring retains the beneficial traits by
merging two of the same species with like physical
characteristics. It was the work of Mendel that actually
led to more educated explanations for the value in
protective resemblance. The Hardy-Weinburg theory
specifically, employs Mendel's theory to a degree to
predict the frequency of occurrence of dominantly or
recessively expressing offspring. Population genetics is
almost sufficient in explaining the basis for protective
resemblance. Here biological evolutionary theory might
obtain its first application to genetic engineering.
Finally, one could suggest that species residing in a
specific area might be placed into two ancestral groups:
those species with origins outside of the area and those
species evolving from ancestors already present in the
area. Because the evolutionary process is so slow, spanning
over considerable lengths of time, it can be predicted that
similar species would be found within comparatively short
distances of each other, due to the difficulty for most
organisms to disperse across an ocean.
These patterns of dispersion are rather complex, but it is
generally maintained by biologists that closely related
species occur in the same indefinite region. Species may
also be isolated by geographic dispersion: they might
colonize an island, and over the course of time evolve
differently from their relatives on the mainland.
Madagascar is one such example - in fact approximately 90
percent of the birds living there are endemic to that
region. Thus as predicted, it follows that speciation is
concurrent with the theory of biological evolution.
There is rarely a sentence written regarding Wallace that
does not contain some allusion to Darwin. Indeed, perhaps
the single most significant feat he performed was to compel
Darwin to enter the public scene. Wallace, another English
naturalist had done extensive work in South America and
southeast Asia (particularly the Amazon and the Malay
Archipelago) and, like Darwin, he had not conceived of the
mechanism of evolution until he read (recalled, actually)
the work of Thomas Malthus - the notion that "in every
generation the inferior would be killed off and the
superior would remain - that is the fittest would survive".
When the environment changed therefore, he determined "that
all the changes necessary for the adaptation of the species
... would be brought about; and as the great changes are
always slow there would be ample time for the change to be
effected by the survival of the best fitted in every
generation". He saw that his theory supplanted the views of
Lamarck and the Vistages and annulled every important
difficulty with these theories.
Two days later he sent Darwin (leading naturalist of the
time) a four-thousand word outline of his ideas entitled
"On the Law Which has Regulated the Introduction". This was
more than merely cause for Darwin's distress, for his work
was so similar to Darwin's own that in some cases it
paralleled Darwin's own phrasing, drawing on many of the
same examples Darwin hit upon. Darwin was in despair over
this, years of his own work seemed to go down the tube -
but he felt he must publish Wallace's work. Darwin was
persuaded by friends to include extracts of his own
findings when he submitted Wallace's work On the Law Which
Has Regulated the Introduction of New Species to the
Linnaean Society in 1858, feeling doubly horrible because
he felt this would be taking advantage of Wallace's
position. Wallace never once gave the slightest impression
of resentment or disagreement, even to the point of
publishing a work of his own entitled Darwinism. This
itself was his single greatest contribution to the field:
encouraging Darwin to publish his extensive research on the
issues they'd both developed.
He later published "Contributions to the Theory of Natural
Selection", comprising the fundamental explanation and
understanding of the theory of evolution through natural
selection. He also greatly developed the notion of natural
barriers which served as isolation mechanisms, keeping
apart not only species but also whole families of animals -
he drew up a line ("Wallace's line") where the fauna and
flora of southeast Asia were very distinct from those of
Prior to full recognition of Mendel's work in the early
1900's, development of quantitative models describing the
changes of gene frequencies in population were not
realized. Following this "rediscovery" of Mendel, four
scientists independently, almost simultaneously contrived
the Hardy-Weinberg principal (named after two of the four
scientists) which initiated the science of population
genetics: exploration of the statistical repercussions of
the principle of inheritance as devised by Mendel. Read
concisely the Hardy-Weinberg principle might be stated as

Alternate paradigms of genes in ample populations will not
be modified proportionately as per successive generation,
unless stimulated by mutation, selection, emigration, or
immigration of individuals. The relative proportion of
genotypes in the population will also be maintained after
one generation, should these conditions be negated or
mating is random.
Through application of the Hardy-Weinberg principle the
precise conditions under which change does not occur in the
frequencies of alleles at a locus in a given population
(group of individuals able to interbreed and produce
fertile offspring) can be formulated: the alleles of a
locus will be at equilibrium. A species may occur in
congruous correspondence with its population counterpart,
or may consist of several diverse populations, physically
isolated from one another. 

In accordance with Mendelian principle, given two
heterozygous alleles A and B, probability of the offspring
retaining prominent traits of either parent (AA or BB) is
25 percent, probability of retaining half the traits of
each parent (AB) is 50 percent. Thus allele frequencies in
the offspring parallel those of the parents. Likewise,
given one parent AB and another AA, allele frequencies
would be 75 percent A and 25 percent B, while genotype
frequencies would be 50 percent AA and 50 percent AB - the
gametes generated by these offspring would also maintain
the same ratio their parents initiated (given, of course a
maximum of two alleles at each locus). 

In true-to-life application however, where numerous alleles
may occur at any given locus numerous possible combinations
of gene frequencies are generated. Assuming a population of
100 individuals = 1, 30 at genotype AA, 70 at genotype BB.
Applying the proportionate theory, only 30% (0.30) of the
gametes produced will retain the A allele, while 70% (0.70)
the B allele. Assuming there is no preference for AA or BB
individuals for mates, the probability of the (30% of total
population) AA males mating with AA females is but 9% (0.3
x 0.3 = 0.09). Likewise the probability of an BB to BB
match is 49%, the remainder between (30%) AA and (70%) BB
individuals, totaling a 21% frequency. Frequency of alleles
in a population in are commonly denoted p and q
respectively, while the AB genotype is denoted 2pq. Using
the relevant equation p + pq + q = 1, the same proportions
would be obtained. It can therefore be noted that the
frequencies of the alleles in the population are unchanged.
If one were to apply this equation to the next generation,
similarly the genotype frequencies will remain unchanged
per each successive generation. Generally speaking, the
Hardy-Weinberg principle will not favour one genotype over
another producing frequencies expected through application
of this law.
The integral relevance for employment of the Hardy-Weinberg
principle is its illustration of expected frequencies where
populations are evolving. Deviation from these projected
frequencies indicates evolution of the species may be
Allele and genotype frequencies are typically modified per
each successive generation and never in ideal
Hardy-Weinberg equilibrium. These modifications may be the
result of natural selection, but (particularly among small
populations) may simply result from random circumstance.
They might also arise form immigration of individuals form
other populations where gene frequencies will be unique, or
form individuals who do not randomly choose mates from
their wide-ranged species.
Despite the lack of respect Lamarckian theory was dealt at
the hands of the early evolution-revolutionaries, the
enormous influence it had on numerous scientists, including
Lyell, Darwin and the developers of the Hardy-Weinberg
theory cannot be denied. Jean Lamarck, a French biologist
postulated the theory of an inherent faculty of
self-improvement by his teaching that new organs arise form
new needs, that they develop in proportion to how often
they are used and that these acquisitions are handed down
from one generation to the next (conversely disuse of
existing organs leads to their gradual disappearance). He
also suggested that non-living matter was spontaneously
created into the less complex organisms who would evolve
over time into organisms of greater and greater complexity.
He published his conclusions in 1802, then later (1909)
released an expanded form entitled "Philosophie
Zoologique". The English public was first exposed to his
findings when Lyell popularized them with his usual flair
for writing, but because the influential Lyell also openly
criticized these findings they were never fully accepted.
Darwin's own theories were based on those of older
evolutionists and the principle of descent with
modification, the principle of direct or indirect action of
the environment on an individual organism, and a wavering
belief in Lamarck's doctrine that new characteristics
acquired by the individual through use or disuse are
transferred to its descendants. Darwin basically built
around this theory, adding that variation occurs in the
passage each progressive generation. Lamarck's findings
could be summarized by stating that it is the surrounding
environment that has direct bearing on the evolution of
species. Darwin instead contested that it was inter-species
strife "the will to power" or the "survival of the
fittest". Certainly Lamarck was looking to the condition of
the sexes: the significantly evolved difference of
musculature between male and females can probably be more
easily explained by Lamarckian theory than Darwinian. There
was actually quite a remarkable similarity between the
conclusions of Darwin's grandfather, Erasmus Darwin and
Lamarck - Lamarck himself only mentioned Erasmus in a
footnote, and with virtual contempt. The fact is neither
Lamarck nor Darwin ever proposed a means by which species
traits were passed on, although Lamarck is usually recalled
as one of those hopelessly erroneous scientists of past it
was merely the basis for his conclusions that were
hopelessly out of depth - the conclusions were remarkably
In 1831 a young Charles Darwin received the scientific
opportunity of lifetime, when he was invited to take charge
f the natural history side of a five year voyage on the
H.M.S. Beagle, which was to sail around the world,
particularly to survey the coast of South America. Darwin's
reference material consisted of works of Sir Charles Lyell,
a British geologist (he developed a concept termed
uniformitarianism which suggested that geological phenomena
could be explained by prevailing observations of natural
processes operating over a great spans of time - he has
been accused synthesizing the works of others) who was the
author of geologic texts that were required reading
throughout the 19th century including Principals of
Geology, which along with his own findings (observing the a
large land shift resulting from an earthquake), convinced
him of geological uniformitarianism, hypothesizing for
example, that earthquakes were responsible for the
formation of mountains. Darwin faithfully maintained this
method of interpreting facts - by seeking explanations of
past events by observing occurrences in present time -
throughout his life. The lucid writing style of Lyell and
straightforward conclusions influence all of his work. When
unearthing remains of extinct animals in Argentina he noted
that their remains more closely resembled those of
contemporary South American mammals than any other animals
in the world. He noted "that existing animals have a close
relation in form with extinct species", and deduced that
this would be expected "if the contemporary species had
evolved form South American ancestors" not however, if
there existed an ideal biota for each environment. When he
arrived on the Galapagos islands (islands having been
formed at about the same time and characteristically
similar), he was surprised to observe unique species to
each respective island, particularly tortoises which
possessed sufficiently differentiated shells to tell them
apart. From these observations he concluded that the
tortoises could only have evolved on the islands.
Thomas Robert Malthus was an English economist and
clergyman whose work An Essay on the Principal of
Population led Darwin to a more complete understanding of
density dependent factors and the "struggle in nature".
Malthus noted that there was potential for rapid increase
in population through reproduction - but that food cannot
increase as fast as population can, and therefore
eventuality will allow less food per person, the less able
dying out from starvation or sickness. Thus did Malthus
identify population growth as an obstacle to human progress
and peddled abstinence and late marriage in his wake. For
these conclusions he came under fire from the Enlightenment
movement which interpreted his works as opposing social
Erasmus Darwin, grandfather of Darwin, was an
unconventional, freethinking physician and poet who
expressed his ardent preoccupation for the sciences through
poetry. In the poem Zoonomia he initiated the idea that
evolution of an organism results from environmental
implementation. This coupled with a strong influence from
the similar conclusions of Lamarck shaped Darwin's
perception on the environment's inherent nature to mold and
shape evolutionary form.
Early scientists, particularly those in the naturalist
field derived most of their conclusions from observed,
unproven empirical facts. Without the means of logically
explaining scientific theory, the hypothesis was incurred -
an educated guess to be proven through experimentation.
Darwin developed his theory of natural selection with a
viable hypothesis, but predicted his results merely by
observing that which was available. Following Lyell's
teaching, using modern observations to determine what
occurred in the past, Darwin developed theories that "only
made sense" - logical from the point of view of the human
mind (meaning it was based on immediate human perception)
but decidedly illogical from a purely scientific angle. By
perusing the works of Malthus did Darwin finally hit upon
his theory of natural selection - not actually questioning
these conclusions because they fit so neatly into his own
puzzle. Early development of logical, analytic scientific
theory did not occur until the advent of philosopher Rene
Descartes in the mid-17th century ("I think therefore I
am"). Natural selection was shown to be sadly lacking where
it could not account for how characteristics were passed
down to new generations. However, it did present enough
evidence for rational thought to be applied to his theory.
Thus scientists were able to develop fairly accurate
conclusions with very limited means of divination.
Opposition from oppressive Judeo-Christian church allowed
little room science. Regardless, natural selection became
the basis for all present forms of evolutionary theory.
Darwinism, while comparatively rational and well documented
nevertheless upheld the usual problem that can be found in
many logical scientific conclusions - namely deliberate
ignorance of facts which might modify or completely alter
years the conclusions of years of research. Many biologists
were less than convinced with an evolutionary hypothesis
that could not explain the mechanism of inheritance. It was
postulated by others that offspring will tend to have a
blend of their two parents characteristics, the parents
having a blend of characteristics from their ancestors, the
ancestors having a blend of characteristics from their
predecessors - allotting the final offspring impure,
diminished desirable characteristics. Thus did they believe
a dilution of desirable traits evolved even more diluted
desirable traits - these traits now decidedly muted. It was
more than two decades after Darwin's death that Mendelian
theory of the gene finally came to light at the turn of the
century. Because of this initial skepticism with Darwin's
natural selection, when Mendel's work became widely
available biologists emphasized the importance of mutation
over selection in evolution. Early Mendelian geneticists
believe that continuous variation (such features as body
size) hardly factored in the formation of new species -
perhaps nothing to do with genetic control. Inferences on
the gradual divergence of populations diminished in wake of
notions of significant mutations.
This gave rise to the neo-Darwinian theory in the 1930's,
or what is called "modern synthesis". It encompasses
several sciences such as paleontology, biogeography,
systematics and, of course, genetics. Geneticists have
noted that acquired characteristics cannot, indeed be
inherited, while observing that continuous variation is
inherited through the effects of many genes and have
therefore concluded that continuously distributed
characteristics are also influenced by natural selection
and evolve through time. Modern synthesis, in other words,
differs little form Darwinian theory, but also incorporates
current understanding of inheritance. Modern synthesis
maintains that random mutations introduce variation into
population, natural selection inaugurating new genes in
greater proportions. Despite revolutionary progress the
discovery of the gene has made, neo-Darwinian theory is
still based on the arbitrary assumption that the primary
factor causing adaptive change in populations is natural
Species have been traditionally described based on their
morphological characteristics. This has proven to be
somewhat premature to say the least: some organisms in
extremely different forms are quite similar in their
genetic make-up. Male and females in many species develop
more than a few many characteristic physical differences,
yet are indeed the same species (imagine that!). Likewise
some organisms appear to be quite morophologically similar
but are completely incompatible. There are many species of
budworm moths, all of which are highly indistinguishable -
most of which do not interbreed.
The idea of species is usually called the biological
species concept, stressing the importance of interbreeding
among individuals in a population as a general description.
An entire population might be thought of as a single unit
of evolution. However similar difficulties arise in
attempting a universal application of this theory. Because
morphologically similar species occur in widely separated
regions, it is virtually impossible to exact whether they
could or could not interbreed. 

One might ask whether cactus finches from the Galapagos
interbreed - the answer may invariably be yes...but due
rather to the morphological similarities between them.
Consider further asexually producing species, which can be
defined by appearance alone: each individual would have to
be defined as different biological species - a fact which
would remain irrelevant. There are also cases for which no
real standard can be applied - the donkey and horse, for
example can mate and produce healthy offspring, mules which
are almost always sterile and therefore something
completely indefinable. Therefore, despite seeming ideal in
its delimitation, the biological species concept cannot be
employed in describing many natural species. It is
nonetheless a popular concept for theoretical discussions
since it can distinguish which populations might evolve
through time completely independent of other similar
Species classification is therefore not defined by fixed
principles surrounding biological and morphological
classifications both. The random nature of evolution itself
is predictable perhaps only in that one respect: that it
remain virtually unpredictable. In accordance with the
Hardy-Weinberg theory the proportion of irregularity should
not necessarily increase, but because, by its own admission
this theory cannot be employed as a standard but merely to
predict results, even it is limited random un-law of nature.
According to the theory of evolution, all life or most of
it, originated from the evolution of a single gene. All
relatives - species descended from a common ancestor - by
definition share a certain percentage of their genes. If
naught else than these genes are of a very similar nature.
A species depends on the remainder of its population in
developing characteristics which allow easier adaptability
to the changing environment. These modified genes will
ultimately express themselves as new species or may be
passed on to other populations within a given species. For
these traits to be expressed individually is certainly not
going to benefit the species (i.e.. the mule retains
remarkable traits but cannot reproduce - they're also a
literal pain in the ass to generate). Nevertheless should
but one individual in a million retain a beneficial
characteristic, opportunity for this to be passed on is
significantly increased. In short order, as per natural
selection highly adapted species can develop where they
were dying out (over centuries to be sure, but dying out
nonetheless) only a ('n evolutionarily) short span of time
ago. Plant breeders especially know the value of the gene
pool. They depend on the gene pool of the wild relatives of
these plants to develop strains that are well adapted to
local conditions (here we refer to comparatively exotic
plants). The gene pool is there for all compatible species
(and that could be a large amount down the line) to partake
of - given the right random conditions and the future for
plant breeders brightens.
There are a number of known factors that are capable of
changing the genetic structure of a population, each
inconsistent with the Hardy-Weinberg principle. Three
primary contributing factors are migration, mutation and
selection and are referred to as systematic processes - the
change in gene frequency is comparatively predictable in
direction and quantity. The dispersive process of genetic
is predictable only in quantitative nature. When species
are sectioned into diverse, geographically isolated
populations, the populations will tend to evolve
differently on account of the following accepted standards:
1 Geographically isolated populations will mutate
exclusively to their population.
2 The adaptive value for these mutations and gene
combinations will differentiate per each population.
3 Different gene frequencies existed before the population
was isolated and are therefore not representative of their
4 During intervals of small population size gene
frequencies will be fluctuating and unpredictable forming a
genetic "bottleneck" from which all successive organisms
will arise.
Gene frequencies can be altered when a given population is
exposed to external populations causing the change in
frequency to be modified as per the proportion of
foreigners to the mainstream population. Migration may be
eliminated between two populations in regions of geographic
isolation, which will isolate in turn, the gene pools
within the population. If this isolation within population
develops over a sufficient span of time the physical
differences between two given gene pools may render them
incompatible. Thus have the respective gene pools become
reproductively isolated and are now defined as biologically
different species. However, speciation (division into new
species) does not arise exclusively from division into new
subgroups inside a population, other aspects might be
equally effective.
The primary source for genetic variability is mutation,
usually the cause of depletion of species' fitness but
sometimes more beneficial. The ability of a species to
survive is dependent on its store of genetic diversity,
allowing generation of new genotypes with greater tolerance
for changing environment. However, some of the best adapted
genotypes may still be unable to survive if environmental
conditions are too severe. Unless new genetic material is
obtained outside the gene pool, evolution will have a
limited range of tolerance for change. Generally speaking,
spontaneous mutations whether they are required or not.
This means many mutations are useless, even harmful under
current environmental conditions. These crippling mutations
are usually weeded out or kept at low frequencies in the
population through natural selection. The mutation rate for
most gene loci is between one in 100 thousand to one in a
million. Therefore, although mutations are the source of
genetic variability, even without natural selection changes
in the population would be unnoticeable and very slow.
Eventually, if the only pressure affecting the locus is
from mutation, gene frequencies will change and fall back
to comparative equilibrium.
The fundamental restriction on the validity of the
Hardy-Weinberg equilibrium law occurs where population size
in immeasurably large. Thus the disseminating process of
genetic drift is applicable for gene frequency alteration
in situations of small populations. In such a situation
inbreeding is unavoidable, hence the primary contributing
factor for change of gene frequencies through inbreeding
(by natural causes) is genetic drift. The larger the sample
size, the smaller the deviation will be from predicted
values. The action of sampling gametes from a small gene
pool has direct bearing on genetic drift. Evidence is
observed via the random fluctuation of gene frequencies per
each successive generation in small populations if
systematic processes are not observed as contributing
factors. From this four basic assumptions have been made
for idealized populations as follows:
1 Mating and self-fertilization in respective subgroups of
given populations are completely random.
2 Overlap of one generation to its successor does not occur
allotting distinct characteristics for each new generation.
3 In all generations and lines of descent the number of
possible breeding individuals is the same.
4 Systematic factors such as migration, mutation and
natural selection are defunct.
In small populations certain alleles, perhaps held as
common to a species, may not be present. The alleles will
have become randomly lost somewhere in the population in
the process of genetic drift. The result is much less
variability among small populations than among larger
populations. If every locus is fixed in these small
populations, they will have no genetic variability, and
therefore be unable to generate new adaptive offspring
through genetic recombination. The ultimate fate of such a
population if it remains isolated is extinction.
Through genetic variation new species will arise, in a
process termed speciation. It is generally held that
speciation occurs as two given species evolve their
differences over large spans of time - these differences
are defined as their genetic variation. The most popular
model use to explain how species formed is the geographic
speciation model, which suggests that speciation occurs
only when an initial population is divided into two or more
smaller populations - via genetic variation through
systematic means of mutation, natural selection or genetic
drift - geographically isolated (physically separated) from
one another. Because they are isolated, gene flow
(migration) cannot occur between the respective new
populations. These "daughter" populations will eventually
adapt to their new environments through genetic variation
(process of evolution). If the environments of each
isolated population are different then they would be
expected to adapt to different conditions and therefore
evolve differently. According to the model of geographic
speciation, the daughter populations will eventually evolve
sufficiently to become incompatible with one another
(therefore unable to interbreed or produce viable
offspring). As a result of this incompatibility, gene flow
could not effectively occur even if the populations were no
longer geographically isolated. The differentiated, but
closely related species are now termed species pair, or
species group. Eventually differentiation will progress far
enough for them to be defined as different species.
While divergence is a continuing process, it does not
necessarily occur at a constant rate - fluctuating between
extremely rapid rates and very slow rates of evolution. Two
standard methods have been postulated for the occurrence of
geographic speciation: i) Individuals from a species might
populate a new, isolated region of a give area (such as an
island). Their offspring would evolve geographically
isolated from the original species. Eventually,
geographical isolation from the population on the mainland
would evolved distinguishable characteristics. ii)
Individuals might, alternately be geographically isolated
as physical barriers arise or the range of the species or
individuals of a population diminishes. However, neither of
these forms of speciation through geographic isolation and
consequent individual genetic variation have been observed
or studied direct because of the time span and general
difficulty of unearthing desired fossils. Evidence for this
form of speciation is therefore indirect and based on
postulated theory.
The finches of the Galapagos Islands provided Darwin with
an important lead towards his development of his theory of
evolution. They were (are) a perfect example of how
isolated populations could evolve. Here Darwin recognized
that life branched out from a common prototype in what is
now called adaptive radiation. There were no indigenous
finches to the islands when they arrived - some adapted to
tree-living, others to cactus habitat, others to the
ground. The differentiation was comparatively small, and
yet there evolved fourteen species of bird classified under
six separate genera, each visibly different only in the
characteristics of its beak. 

Joint selection pressure equations have been used to
calculate the change in gene frequency and consequent rate
of mutation resulting from action the of natural selection.
Populations of Galapagos finches arrived at their islands
from South America and were provided with varying methods
of obtainment of sustenance. Only those individuals that
evolved characteristics allowing them to more easily obtain
food from varying sources, were not selected against.
Populations were isolated on certain islands and had to
adapt to different food sources. The result was an
adaptation to food (seeds) from trees, ground or
cactus-dominated areas. However, the migratory nature of
these finches prompted them to emigrate to alternate
islands, therefore interbreeding with otherwise isolated
populations of finches. The result has been a variation on
single specific characteristics which retain certain
properties due to the singular islands they predominantly

When the population of immigrants was high enough, the gene
pools of diverse populations of finches presently occupying
the island was modified enough such that offspring would
inherit some of the traits of otherwise isolated finch
populations. Nevertheless, these finches developed
characteristics endemic to their particular habitat, and
because finches tend to remain in groups rather than
individual families, these particular characteristics
became dominant enough to evolve morphologically and later
even biologically different characteristics. These
discrepancies could only lead to greater genetic variation
down the line. 

Eventually immigrants from the mainland and even other
Galapagos Islands were completely incompatible with
specific finch populations endemic to their respective
islands. Generally, selection pressure decreased as
mutations resulting from systematic processes of genetic
variation could no longer occur. This produced a
significantly less versatile gene pool, however, via
genetic drift from individuals of alternate populations who
had, at some point evolved from ancestors the population in
question. Thus the gene pool could be modified without
really affecting the gene frequencies - joint pressures
were therefore stabilized, along with the newly developed
Speciation is substantially more relevant to the evolution
of species than convergent evolution. Through natural
selection similar characteristics and ways of life may be
evolved by diverse species inhabiting the same region, in
what is called convergent evolution - reflecting the
similar selective pressure of similar environments. While
separate populations of the same species occupying similar
habitats may also evidence similar physical characteristics
- due primarily to the environment rather than their
species origin - it should noted that they progressed form
the same ancestor. A defining principle for the alternate
natures of speciation and convergent evolution put simply:
speciation results form a common ancestor, convergent
evolution results from any number of ancestors.
Morphologically similar populations resulting from the same
ancestor may be compatible and able to produce viable
offspring (if in some occasions not fertile offspring).
Morphologically similar species resulting form different
ancestors are never compatible with one another - even if
they are virtual morphological twins. In fact,
morphologically disparate populations of the same species
may be compatible with one another - whereas those
disparate through convergent evolution would be more than
merely incompatible, they may be predator and prey.
Convergent evolution may only account for single specific
physical characteristics of very disparate, unrelated
species - such as the development of flipper-like
appendages for the sea turtle (reptile), penguin (bird) and
walrus (mammal).
If individuals were unable to adapt to changes in the
environment they would be extinct in short order.
Adaptability is often based on nuclear inheritance down the
generations. Should an organism develop a resistance to
certain environmental conditions, this characteristic may
be passed down through the gene pool, and then through
natural selection be dominant for all organisms of a given
Bacteria are able to accomplish this feat at a remarkably
fast rate. Most, if not all forms of bacteria are
compatible with one another, that is able to exchange
genetic information. The speed at which bacteria reproduces
is immeasurably faster than that of more complex, eukaryote
organisms. Bacteria have a much shorter lifespan as well -
but because they can develop very quickly into large
colonies given ideal conditions, it is easier to understand
bacteria in clusters. Should a single bacterial organism
develop a trait that slightly aids its resistance to
destructive environmental conditions, it can pass its
modified genetic structure on to half of a colony in a
matter of hours. In the meantime the colony is quickly
expanding, fully adapted to the environment - soon however,
it has developed more than it can be accommodated. The
population will drop quickly in the face of inadaptability.
But that (previously mentioned) exterior bacterial organism
with the modified trait releases information yielding new
growth, allowing the colony to expand further. 

It is generally accepted that bacterial colonies will
achieve a maximum capability - however, through adaptation
the bacterial population will quickly excel once again.
Antibiotics are now sent to destroy the bacteria. Soon they
will be obliterated - and now all that remains of the
colony are a few choice bacterial organisms. However, an
otherwise isolated bacteria enters the system to exchange
genetic information with the much smaller bacterial colony,
conditions are favourable, the bacteria expands again.
Antibiotics are sent again to destroy this colony - but the
exterior bacteria, originating in another organism and
having developed a resistance to this type of antibody has
provided much of the colony with the means for resistance
to these antibodies as well. 

Once again the bacterial culture has expanded having
resisted malignant exterior interlopers. This is how
bacteria develops, constantly exchanging nuclear
information, constantly able to adapt to innumerable
harmful sources. As bacteria are exposed to more
destructive forces, the more they develop resistance to, as
surely many of the billions of bacteria could develop an
invulnerability to any threatening exterior sources given
ideal environmental conditions.
Recently the concept of punctuated equilibrium, as proposed
by American paleontologist Stephen Jay Gould has be the
subject of much controversy in the scientific world. Gould
advanced the idea that evolutionary changes take place in
sudden bursts, and are not modified for long periods time
when they are reasonably adapted to altered environment. 

This almost directly contradicts the older, established
Darwinian notions that species evolve through phyletic
gradualism, that evolution occurs at a fairly constant
rate. It is not suggested by adherents of the punctuated
equilibrium model that pivotal fluctuations in morphology
occur spontaneously or in only a few generations changes
are established in populations - they argue instead that
the changes may occur in but 100 to 1000 generations. It is
difficult to determine which model could more adequately
describe what transpires over the course of speciation and
evolution due to gaps in fossil-record, 50 to 100 thousand
years of strata often covering deposits bearing fossils.
Genetic make-up need not change much for rapid, discernible
morphological alterations to detected.
Impartial analysts on the two theories conclude that they
are both synonymous with evolutionary theory. Their primary
differences entail their emphasis on the importance of
speciation in long-term evolutionary patterns in lineage.
While phyletic gradualism emphases the significance of
changes in a single lineage and the revision of species
through slight deviation, punctuated equilibrium emphases
the significance of alteration occurring during speciation,
maintaining that local (usually small) populations adapt
rapidly to local circumstance in production of diverse
species - some of which acquire the means for supplantation
of their ancestors and rampant settlement in many important
adaptive breakthroughs. One must consider that Darwin was
not aided by Mendelian theory. Under such circumstances
Darwin would have surely produced an entirely different
theory for the inheritance of beneficial traits. Consider
that mutations can presumably occur spontaneously, given
the properly modified parent. It can therefore be stated
that punctuated equilibrium is probably a more likely
explanation as it does take into account modern cell, and
genetic theory. Phyletic gradualism, while certainly
extremely logical is a theory which simply cannot encompass
those circumstance in which significant change is recorded
over comparatively short periods of time. Both are
complementary to be sure, but perhaps one of the two
distorts this complementary nature formulating inaccurate
Whether or not the theory of evolution is useful depends on
whether or one values progress above development of
personal notions of existence. Certainly under the blanket
of a superficial American Dream one would be expected to
subscribe to ideals that society, that the state erects. Of
course, these ideals focus on betterment of society as a
whole - which now unfortunately, means power to the state.
Everybody is thus caught up in progress, supposedly to
"improve the quality of life", and have been somewhat
enslaved by the notion of work. Work has become something
of an idol, nothing can be obtained without work - for the
state. Whether one agrees with the thoughtless actions of
the elite or not, people are oppressed by conforming to
ideals that insist upon human suffering. Some
irresponsible, early religious institutions did just that,
erecting a symbol of the people's suffering and forcing
them to bow before it. Development of aeronautic, or even
cancer research contributes primarily to this ideal of
progress. Development of such theories as biological
evolution, contribute nothing toward progress. It instills
in the people new principles, to dream and develop an
understanding of themselves and that which surrounds them
ones, freeing their will from that shuffling mass,
stumbling as they are herded towards that which will reap
for them suffering and pain. The state provides this
soulless mass with small pretty trinkets along the way,
wheedling and cajoling them with media images of how they
should lead their lives - the people respond with regrets. 

Modern theory of biological evolution is actually sadly
lacking in explanation for exactly how characteristics are
passed down to future generations. It is understood how
nitrogen bases interact to form a genetic code for an
organism - but how the modification that the organism
develops, occurs is unknown. Somehow the organism mutates
to adapt to environmental conditions, and then presumably
the offspring of this organism will retain these
adaptations. Of course, biological evolution cannot also
explain precisely how first organisms developed: Generally,
the theory accounts for energy and chemical interactions at
a level consistent enough to establish a constant flow of
said interactions - but even here it falls short. And what
of phyletic gradualism? It is completely unable to explain
the more sudden mutations that occur...for obvious reasons
it cannot explain this (Darwin had no knowledge of
genetics), but even punctuated gradualism doesn't balance
this problem. I'm sure there are numerous other problems
which can be addressed but these can be dealt with where
opinion can be more educated.
Man it would appear, has always sought meaning for his
existence. Development of many theories of existence have
been conceived and passed down through the ages.
Institutions conferring single metaphysical and elemental
viewpoints have been established, some of which have been
particularly irresponsible and oppressive towards the
people they were supposed to "enlighten". Most religious
institutions have been used as political tools for means of
manipulation of the masses, going back to early Roman days
when empower Augustus absorbed Christianity into the Roman
worship of the sun, Sol Invectus, as a means of subjugating
the commoners to Roman doctrine. Generally religious
institutions have exploited the people and have been used
as excuses for torture, war, mass exterminations and
general persecution and oppression of the people it
pretends to serve, telling the people they must suffer to
reach ultimate transcendent fulfillment. Unfortunately this
oppression continues in today's modern - even Western -
world. There have actually been almost innumerable
explanations for the physical presence of man - these
explanations merely been suppressed by the prevailing
religious institutions for fear that they will be deprived
absolute power over the people...they're right.
Without Darwin it can be concluded, reasonable
interpretation of biological evolution simply would not be.
Natural selection, the process determining the ultimate
survival of a new organism, remains the major contributing
factor to even the most modern evolutionary theory. The
evolutionary process spans over the course of hundreds of
thousands of generations, organisms evolving through
systematic and dispersive mechanisms of speciation.
Recently, heated debate surrounding whether characteristics
are passed on in bursts of activity through punctuated
equilibrium or at a constant rate through the more
traditional phyletic gradualism. The release of Mendelian
theory into the scientific community filled the primary
link missing in Darwin's theory - how biological
characteristics were passed on to future generations.
Applications of genetic theory to evolutionary theory
however, are somewhat limited. It is difficult to classify
all species even through modern means of paleontology and
application to the theory of organic evolution.
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Dawkins, Richard. The Selfish Gene. New York: Paladin, 1978.
Farrington, Benjamin. What Darwin Really Said. New York:
Shoken Books, 1966.
Gailbraith, Don. Biology: Principals, Patterns and
Processes. Toronto: John Wiley and Sons Canada Ltd. 1989,
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Glass, Bently. Forerunners of Darwin 1745-1859. New York:
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Gould, S.J. Ever Since Darwin. New York: Burnett Books,
Grolier Encyclopedia, New. New York: Grolier Publishing,
Inc., 1991.
Haldane, J.B.S. The Causes of Evolution. London: Green and
Co., 1982. 

Leakey, Richard E.. Mankind and Its Beginnings. New York:
Anchor Press/Doubleday, 1978.
Miller, Johnathan. Darwin For Beginners. New York: Pantheon
Books, 1982.
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Natural History Press, 1976.
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Book Company, 1983, p.266-287.
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