Evolution Essay, Research Paper
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 ever1. 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 interpret2).
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)3, but wide-range acceptance of this idea, beyond the bounds of the
scientific community, did not arise until Darwin published his findings in
19584. 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 growth5. 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 puzzle6. 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)7, 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 individuals8.
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 population9.
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”10. 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 muted11.
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 irregular12.
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 evolution13.
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
evolution14.
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 theory15.
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 ancestor16.
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 resemblance17. 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 engineering18.
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 evolution19.
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
scene20. 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 theories21.
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 developed22.
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 Australasia23.
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
random24.
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 another25.
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
species26.
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 accepted27.
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”28. 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 accurate29.
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 others30) 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 life31. 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 islands32.
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 reform33.
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 form34.
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”35). Natural selection was shown to be sadly lacking where
it could not account for how characteristics were passed down to new
generations36. 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.37
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
characteristics38. 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 century39.
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 mutations40.
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 selection41.
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 interbreed42.
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 species43. 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 nature44.
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 brightens45.
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 arise46.
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 effective47.
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
equilibrium48.
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 defunct49.
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 extinction50.
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 populations51. 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 diminishes52.
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 theory53.
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 beak54.
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 populations55. 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 islands56. 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 frequencies57 – 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 ancestors58.
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)59.
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 again60. 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
interlopers61. 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 environment62.
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 detected63.
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 breakthroughs64.
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 adaptations65. 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
gradualism66. 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.