FREE ESSAY ON EVOLUTION - EXPLANATORY THEORIES II

EVOLUTION - EXPLANATORY THEORIES II

Evolution : Explanatory Theories
TABLE OF CONTENTS
INTRODUCTION
DARWINIAN THEORY OF EVOLUTION
THE THEORY OF BIOLOGICAL EVOLUTION:
CONTRIBUTING ELEMENTS
WALLACE'S CONTRIBUTIONS
HARDY-WEINBERG PRINCIPLE
COMPARISON: LAMARCK vs. DARWIN
DARWIN'S INFLUENCES
METHODS OF SCIENTIFIC DEDUCTION
LIMITS TO DARWIN'S THEORY
MORPHOLOGICAL & BIOLOGICAL CONCEPTS
BIO-EVOLUTION: POPULATION vs. INDIVIDUALS
MECHANISMS FOR GENETIC VARIATION
GENETIC VARIATION AND SPECIATION
DARWIN'S FINCHES
SPECIATION vs. CONVERGENT EVOLUTION
CONCEPT OF ADAPTATION
PUNCTUATED EQUILIBRIUM
VALUE/LIMITATIONS: THE THEORY OF BIOLOGICAL EVOLUTION
ALTERNATE EXPLANATIONS OF BEING
CONCLUSIONS
INTRODUCTION
Theories explaining biological evolution have been bandied about since the ancient
Greeks, but it was not until the Enlightment 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.
I've assessed and interpreted the basis of Darwin's theories on evolution, incorporating
a number of other factors concerning evolutionary theory in the process. Criticism of
Darwin's conclusions abounds somewhat more than has been paid tribute to, however
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).
Evolutionary and revolutionary in more than one sense of each word. Every theory
mentioned in the following reading, in fact falls back to Darwinism.
DARWINIAN THEORY OF BIOLOGICAL EVOLUTION
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 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 offspring 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
advance to his present level in love, memory, attention, curiosity, imitation, reason,
etc. as well as progress in knowledge 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 (ie. 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
decrease.
6 Predator and prey have no underlying purpose for maintenance of any type of balance -
natural selection is opportunistic and irregular.
THE THEORY OF BIOLOGICAL EVOLUTION: CONTRIBUTING ELEMENTS
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, behaviourial, 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 (ie. 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 ancestor.
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.
WALLACE'S CONTRIBUTIONS
There is rarely a sentence written regarding Wallace that does not contain some allusion
to Darwin. Indeed, perhaps the single most significant feat he preformed 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 parallelled 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 Australasia.
HARDY-WEINBERG PRINCIPLE
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 follows: 
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, totalling 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 occurring.
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.
COMPARISON: LAMARCK vs. DARWIN
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 accurate.
DARWIN'S INFLUENCES
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
thereexisted 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 pedalled abstinence and late marriage in his wake. For
these conclusions he came under fire from the Enlightment movement which interpreted his
works as opposing social reform.
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 mould and
shape evolutionary form.
METHODS OF SCIENTIFIC DEDUCTION
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.
LIMITS TO DARWIN'S 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 scepticism 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 neo-Darwinian theory in the 1930's, what is called modern synthesis
which encompasses 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 selection.
MORPHOLOGICAL & BIOLOGICAL CONCEPTS
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 undefinable. 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 populations.
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.
BIO-EVOLUTION: POPULATION vs. INDIVIDUALS
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 (ie. 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.
MECHANISMS FOR GENETIC VARIATION
There are a number of known factors 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 ancestors.
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, the change in frequency 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
that 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.
GENETIC VARIATION & SPECIATION
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.
DARWIN'S FINCHES
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 ares. 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 occupied. 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 population.
SPECIATION vs. CONVERGENT EVOLUTION
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).
CONCEPT OF ADAPTATION
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 population.
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 (previosly 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 decelop resistace to, as surely
many of the billions of bacteria could develop an invulnerability to any threatening
exterior sources given ideal environmental conditions.
PUNCTUATED EQUILIBRIUM
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, discernable 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
assumption.
VALUE/LIMITATIONS: THE THEORY BIOLOGICAL EVOLUTION 
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.
ALTERNATE EXPLANATIONS OF BEING
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 fulfilment. 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.
CONCLUSIONS
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.
Bibliography
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ENDNOTES