FREE ESSAY ON HOW DID LIFE REALLY BEGIN?

HOW DID LIFE REALLY BEGIN?

HOW DID LIFE REALLY BEGIN? 
INTRODUCTION
Evolution. Is it a fact or fiction? I thought that Evolution, was just a theory, but I
was wrong. I believe that Darwin's theory has had a great impact on the world today. It
has caused many debates between religious authorities and those from the scientific
community. This theory had prompted individuals to think about the Origin of the
Universe, Earth, and how did life really begin.
However, what distinguishes Charles Darwin from the others is the fact that he collected
and provided substantial evidences and he related various branches of science such as
geology, botany and biology, which helped, validate his theories. His theory of natural
selection as stated by Nelson and Jurmain (1991, p.606) in the modern form is that the
evolutionary factor causes changes in allele frequencies in populations due to
differential net reproductive success of individuals. His grasp of the evolutionary
process and the clarity of his work makes Charles Darwin the most popular figure in the
scientific field of Evolution (Francoeur, 1965, p.34).
The grandfather Erasmus Darwin (1731-1802) was a well renowned doctor, poet and
philosopher who wrote many books concerning nature. He said that all different living
things were produced over millions of years by one original ancient parent, such that
each offspring had a natural tendency to improve itself (Karp, 1968, p.14). However,
fossil records show that this theory of one original parent was not probable (Karp, 1968,
p.14). His opposition toward any form of organized religion and his rejection of
Christianity was considered to be superficial and eccentric (Chancellor, 1973, p.21). His
tendency to theorize and create wild speculations without testing his theories caused his
reputation as a scientist to suffer.
Around the end of the eighteenth century all discussions of evolution were suppressed
because of the rigid creationist views held by the Church who persecuted anyone who
challenged their beliefs (Chancellor, 1973, p.41). It was not until the publication of
Charles Darwin's The Origin of Species that the discussion of evolution was revived.
When non-biologists talk about biological evolution they often confuse two different
aspects of the definition. On the one hand there is the question of whether or not modern
organisms have evolved from older ancestral organisms or whether modern species are
continuing to change over time. On the other hand there are questions about the mechanism
of the observed changes... how did evolution occur? Biologists consider the existence of
biological evolution to be a fact. It can be demonstrated today and the historical
evidence for its occurrence in the past is overwhelming. However, biologists readily
admit that they are less certain of the exact mechanism of evolution; there are several
theories of the mechanism of evolution.
EVOLUTION AND FOSSIL RECORD
In the study of human evolution, two main methods of dating are used: 
? Carbon-14 and potassium-argon dating. Carbon-14 dating involves the decay of
radioactive C-14, which has a half-life of 5770 years. This makes this method useful for
dating of recent fossils, with good accuracy, up to 50,000 years back. After 5770 years,
half of the carbon-14 in a fossil decays to nitrogen-14. Since the ratio of carbon-12 to
carbon-14 in a living organism remains the same as in the environment around them because
the organism constantly eats and replenishes it, if it were to die, the ratio would
change greatly after many years. It is the difference between this ratio now and the time
is died that allows a date for it to be established.
? Potassium-argon dating, another dating method, is possible due to volcanic ash and
rocks found near many fossil sites. Rocks and ash created in this manner contain
potassium-40, but no argon. As time passes, the potassium-40 decays into argon-40. In the
laboratory, the sample is reheated, and since argon-40 is a gas, it is released. The
ratio of argon-40 released to potassium-40 still present allows for a date to be assigned
to objects near the sample. However, due to potassium's high half-life (1.3 billion
years), it is only useful as a dating technique for finds older than 500,000 years old.
Also, it is only useful where volcanic activity existed. Both these methods have error
margins, ranging from a few thousand years in carbon-14 dating to tens of thousands of
years, or more, for potassium-argon dating. However, thanks to scientific breakthroughs,
these two processes can be used with reasonable security in establishing a time for
fossils.
Our farthest believed ancestor is believed to be Australopithecus afarensis. This
species, which lived between three and four million years ago, is believed to be the
first real hominid because it is the oldest, and most primitive of any definite hominid
form thus far found.(Turnbaugh, 281) Evidence from fossilized footprints, as well as
pelvic and leg bones which were similar to modern hominids, led scientists to believe
that they could walk upright. Its teeth resembled more those of primates, due to their
large size. Its skull capacity ranged from 350 to 500 cm3. This species, though it had
some hominid characteristics, was still more like an ape. Its face protruded outwards
near the mouth region, and it did not have a definable chin. Finally, their craniums had
large, protruding ridges over the eyes.
Another important being in the human timeline is Australopithecus africanus. Many
scientists believe that it is the next in the sequence leading to man, however, a few
believe that it belongs to a lineage on its own. Africanus fossils have been dated back
to the time period between two and three million years ago. It had a greater body size
than Afarensis, and a skull volume ranging between 420 and 500 cm3. It averaged a little
higher in height than the 3 ? to 5 feet believed for Afarensis. Its jaws also protruded
out. The keel effect is very distinguishable on this species, as it is with many of the
older hominid species a slight peak on the top of the cranium. Ridges over the eyes were
also prominent on this hominid.
The next species believed to be in our line of descent is Homo habilis. This is the first
being with the distinction of having Homo as its genus. This species, which is dated back
to between 1.5 and 2.4 million years ago, had a face, which protruded less than Africanus
and Afarensis. Its teeth, though still larger than modern humans, were smaller than those
of its ancestors. Finally, its fossil fragments displayed an average increase in cranial
size of 21 percent and 43 percent, respectively, over [Africanus and
Afarensis],(Turnbaugh, 288) with an average cranial capacity of 650 cm3. Skulls found of
this hominid also feature a bulge of Broca's area, an area essential for human speech. It
was also taller than the previous hominids, averaging around 5 feet high.
At about the same time as Homo habilis and some of the other Homo species, other hominid
species belonging to the Australopithecus genus, are believed to have co-existed. Though
similar to the Homo line in structure, their bones were thicker and more robust. These
other hominids are believed to have developed on a different lineage than the Homo line,
and all of these streams died out at around the time of Homo erectus, the next key
hominid on the human lineage. Because they are believed to have evolved apart from Homo
hominids, it is not important to cover these species in detail. Homo erectus lived
between 300,000 and 1,800,000 years ago, and still had protruding jaws and a keel effect
on the top of the cranium. It, like its predecessors, had no definable chin, and thick
brow ridges. However, skull capacity in these hominids jumped from an average of 650 cm3
in H. habilis to an average of 900 cm3 in early specimens and 1100 cm3 in later
specimens. The skeleton is more robust than those of modern humans, implying greater
strength.(Foley, w. page.) Due to their larger brain sizes, they are believed to have
possessed greater intelligence, and evidence of this has been found in their probably use
of fire, as shown by traces of burnt bones in cave floors, and the finding of more
sophisticated tools than H. habilis. They were shorter, on average, than Homo sapiens,
and their craniums showed a Nuchal torus, or a ridge, across the back of the head. This
species also had keeled craniums.
Archaic Homo sapiens, which first appeared 500,000 years ago, are believed to be our most
recent relatives. By this time, the keel that existed on their skulls is non-existent,
and the supra-orbital torus (the brow ridge) has begun to recede. Cranial volume has been
measured at an average of 1200 cm3. Fossil evidence shows a trend for their posterior
teeth to have reduced in size, and the anterior teeth to have increased in size, from
previous Homo species, while late archaic Homo sapiens finds show a general reduction in
the size of both areas. The face and jaw areas also showed a reduction in size from
previous species.
It is at this point that Homo sapiens neanderthalensis enters the picture. Commonly known
as Neanderthal Man, this species is believed by most scientists to have existed at the
same time as late archaic Homo sapiens and early Homo sapiens, our own species. Many
scientists theorize that either we killed them off, or interbred with them to produce
modern humans. Their craneal volume is in fact higher than modern humans, at an average
of 1450 cm3. Their bones were also thicker, which implies greater bulk in body. They also
had larger nose cavities, a weak chin, and a protruding jaw area. Neanderthals would have
been extraordinarily strong by modern standards, and their skeletons show that they
endured brutally hard lives.(Foley, w. page) Neanderthal skeletons have been dated to
between 30,000 and 230,000 years ago.
Finally, our own species is encountered. Scientists have dated the earliest Homo sapiens
fossils back 120,000 years. Our species showed an increase in skull capacity up to an
average of 1350 cm3. The supra-orbital ridge is all but gone with modern humans, and
other features seen in earlier Homos, such as the keel and the craneal ridges on the back
are also gone. The cranium is more rounded, as opposed to the general pentagon shape seen
in earlier hominids. Teeth size for modern humans shows a decrease in size from archaic
Homo sapiens. Also, bone size shows a trend towards reduced robustness, with thinner
bones and smaller jaws. From all the fossil evidence, a rough line can be drawn for human
evolution, starting from A. afarensis and ending in H. sapiens. A clear progression of
features, especially in the cranial region, can be seen. Features such as brain size are
seen to have developed and increased from our earliest ancestors up until now, while
other non-essential features, like a furry skin, a supra-orbital ridge, and large teeth,
have diminished. 
This shows evolution of our species, from a more primitive creature, to our modern shape,
which is highly adaptive, intelligent, and suited to any environment. In any meaningful
sense evolution is a fact, but there are various theories concerning the mechanism of
evolution. Is this how Life Really began? Did God created the perfect creature, a
creature that evolves to suit its needs? 
Bibliography:
1. Nelson, Harry & Jurmain, Richard. 1991, Introduction to Physical Anthropology St.
Paul: West Publishing Company.
2. Francoeur, Robert T. 1965, Perspectives in Evolution Baltimore: Helicon. 
3. Karp, Walter. 1968, Charles Darwin & the Origin of Species: Horizon Caravel Books.
4. Chancellor, John. 1973, Charles Darwin, London: Weidenfeld and Nicolson.
5. Eldredge, Niles. Life Pulse: Episodes From the Story of the Fossil Record. New York:
Facts On File Publications, 1987
6. Introduction to Evolutionary Biology. [January 7, 1996] by Chris Colby - www on 26th
Nov. 2000. http://www.talkorigins.org/origins/faqs-evolution.html
7. Foley, Jim. Hominid Species. The Fossil Hominids FAQ. 1997 - www on 26th Nov. 2000.
http://www.ics.uci.edu/pub/origins/fossil-hominids/species.txt 
8. Johanson, Donald and Edey, Maitland. Lucy: The Beginnings of Humankind. New York:
Simon & Schuster, 1981.
9. Rak, Yoel. "The Australopithecine Face." New York: Academic Press, 1983.
10. Turnbaugh, William A., et al., Understanding Physical Anthropology and Archaeology,
5th Edition. Minnesota: West Publishing Company, 1993.