FREE ESSAY ON DARWIN

DARWIN

On the voyage of the Beagle (1831-1836) Darwin collected and described thousands of
animals and plants. In South America he observed the adaptations of organisms to a
variety of habitat from jungle to grassland to mountain habitats. In the temperate
regions the species resembled more closely the species of the tropical regions of South
America rather than the corresponding species of the temperate regions of Europe. For
example, in the grasslands of Argentina there are no rabbits, however, there are rodents
that resemble rabbits; these rodents are unrelated to European rabbits but are similar to
other rodents in South America. Moreover, the fossils in South America are dissimilar to
European fossils but have similarities with extant (i.e. currently living) plants and
animals in South America.
Darwin was particularly intrigued by the finches on the islands of Galapagos which are
located approximately 500 miles from the mainland of South America. These finches,
although unique to these islands, were clearly related to mainland species. There were 14
different species or genera of Galapagos Finch and their bills were adapted for
particular diets. Darwin amassed these and other data including observations on
variability in domestic animals (for example, dogs) which had been brought about by
generations of selective breeding.
As well as drawing on his own observations, Darwin drew from the work of Linnaeus,
Cuvier, Hutton, Lyell, Malthus and Lamarck. In the hierarchial classificatory system of
Linnaeus there is a tacit acknowledgement of relatedness, for example, species belonging
to one genus have more in common with each other than they do with species belonging to
another genus. Linnaeus was a creationist - as evidenced by his egotistical proclamation
God creates, Linnaeus arranges. Cuvier, also a creationist, was a comparative
morphologist (he described the similarity/dissimilarity in anatomy of diverse animals).
Cuvier founded the science of paleontology and described the differences between the
fossil flora and fauna in different strata of rock: he observed that the more recent
strata had fossils that more closely resembled extant organisms. Cuvier believed that the
discontinuities between fossils in different strata were brought about by catastrophes
such as floods which caused the extinction of many species living at a particular time.
This interpretation of earth's history is termed catastrophism and was also held by many
contemporary geologists. By contrast, Hutton and subsequently Lyell held that geological
processes are slow and subtle but that over prolonged periods of time (millions of years)
these can lead to major changes; implicit in this viewpoint is an age for the earth
radically different from the 6,000 years of the biblical creationists.
Other key influences on Darwin were Malthus who had concluded that war and famine were
inevitable as the human population grew more rapidly than available resources, and
Lamarck who had proposed a theory of evolution based on a continuous process of gradual
modification due to acquired characteristics.
Both Darwin and Wallace brought together a multitude of facts including the geographical
distribution of organisms, comparative morphology of living organisms and their fossil
precursors. They postulated that long-term environmental changes including movement of
land masses and changes in climate could have served in the process of natural selection
over many generations with the result that diverse species arose from ancestral types.
Darwin termed this descent with modification (the term evolution was introduced later, as
was the tautology survival of the fittest). Darwin's ideas can be summarized in his own
words from The Origin of Species:
As many more individuals of each species are born than can possibly survive, and as
consequently there is a frequently recurring struggle for existence, it follows that any
being, if it vary in any manner profitable to itself, under the complex and sometimes
varying conditions of life, will have a better chance of survival and thus be naturally
selected. From the strong principle of inheritance, any selected variety will tend to
propagate its new and modified form. 
In assessing the contribution of Darwin and Wallace it should be noted that the key role
in heredity of the nucleus, chromosomes and DNA were not demonstrated until 1892, 1903,
1943, respectively. Also, the Darwin-Wallace theory of evolution was developed without an
appreciation of Mendel's work on inheritance (ironically, Mendel had written to Darwin
with his ideas but Darwin overlooked their significance).
Subsequent studies have drawn closely together the fields of evolution, genetics and
molecular biology. For example, the inherited disease of sickle-cell anemia is caused by
a minor change in DNA which causes a minor change in the hemoglobin protein of red blood
cells. Individuals with two sickle-cell genes suffer sickness and may die, but those
individuals with one sickle-cell gene have a greater resistance to malaria. Thus it can
be seen that this gene may have a survival advantage for Africans in malarial areas. Not
all changes in DNA produce such dramatic effects in proteins and in the individuals who
possess those proteins. Some changes in DNA cause only minor effects or may have no
tangible effects on the organism. By systematically comparing the DNA of different
organisms it is possible to determine the degree of similarity/dissimilarity between
organisms and thus determine phylogenetic (i.e., evolutionary) relationships between
them. For example, in the case of human phylogeny both skeletal structure (comparative
morphology) and gene structure (molecular biology) indicate that humans are more closely
related to chimpanzees than to New World monkeys. He also wrote The Descent Of Man.
In 1974, a discovery was made that dramatically popularized the issue of human evolution.
In Hadar, Ethiopia, Dr. Donald Johanson unearthed a strange primate skeleton. Although it
would be four years before Australopithecus afarensis was declared a new species, A.L
288-1 -- better known as Lucy -- soon became a cultural icon. [photo of Lucy specimen]
Johanson had been searching for Lucy or something like her for almost a year when the
skeleton came to light. In 1973, he and another paleontologist had found a knee joint
they could not classify washed out of a river in Hadar. Suspecting that other members of
the same species were buried in the area, Johanson began to dig. Lucy was the result. 
Several things struck Johanson about his find. First, it appeared to be of the same
species as the 1973 knee joint. Second, the remains were clearly female. Finally -- and
this is by far Johanson's most important claim -- he believed that this primate had
walked upright. 
As soon as the news hit the presses, Lucy became a superstar. Creationists quickly
declared that Lucy was not a hominid, but only an ape. Allegations were made that
Johanson had tampered with the evidence in order to become famous. Evolutionists argued
that Lucy was a perfect example of a transitional hominid, closely related to both humans
and an ancient, undiscovered ancestor of boths humans and modern apes. 
What Was Lucy?
More than two decades after her discovery, debate still smoulders over Lucy's identity.
Was Australopithecus afarensis truly an ancestral human? Or were they merely apes, now
long extinct? 
Although Lucy is by far the best-known example of Australopithecus afarensis, about 300
separate individuals have been found since 1973. Using argon-argon dating and other
techniques rejected by Creationists as inaccurate, Evolutionists have determined ages of
between 3 and 4 million years for Australopithecus afarensis remains. The Lucy specimen
herself has been dated at 3.2 million years. Creationists say these methods are arbitrary
and wrong. Evolutionists maintain they are accurate. 
Modern opinions about Australopithecus afarensis vary. Evolutionists now speculate that
Lucy and her species were ancient relatives of modern humans, although not necessarily
direct ancestors. According to the evolutionary perspective, Lucy could be considered a
sort of great-aunt rather than a great-grandmother to modern humanity. Evolutionists
point to anatomical evidence in the afarensids that indicates Lucy's species was capable
of walking upright in a manner unlike any modern apes. Evolutionists view this as the
first step towards full humanity. 
Creationists, on the other hand, believe Lucy has been misinterpreted. They insist that
Lucy was just another ape, and that her species was almost identical to the chimpanzees
of today. Although they agree that Lucy may have walked upright now and then, they point
out that modern chimpanzees are also capable of an occasional upright stroll.
Creationists emphasize the ape-like features of Australopithecus afarensis. They feel
there is little or no evidence that the species was a product of evolution. 
What is the truth about Lucy? That is for you to decide. The Lucy Test was developed as a
springboard for people interested in the topic of human evolution. I hope you will pursue
this topic further and research it to your heart's content. Take The Lucy Test. Your
results may surprise you. 
What are some of the features that make us different.
There are lots of features that make us unique. We are the only species that has an
opposable thumb. We are also the only ones that are able to walk upright. 
Why do I think people have a hard time accepting human evolution.
I think people have trouble accepting human evolution for many reasons. I think they are
afraid of what they don't want to accept not to mention damn stubborn. I also think that
they want to belong to some great force like they think is there god. I personally don't
believe in god. I accept the concept.