Evolution -Them-to Us Essay

This essay has a total of 2487 words and 9 pages.

Evolution -Them-to Us

The origins of mankind is an extremely controversial issue within today's society.
Scientists have a host of different theories pertaining to man's inhabitance of earth.
Many disagreements arise between scientists who have different beliefs pertaining to where
and how mankind arose. One such argument is the conflict involving the theory of evolution
versus the theory of creation. After extensive scientific research, it is apparent that
the theory of evolution is correct. Evolution is the theory that life arose by natural
processes at an early stage of the earth's history and that complex organisms developed
from simpler organisms by a process of slow change. It is the idea that new species rise
from older species after thousands of years of gradual chemical, environmental, and
genetic change. Evolution can be described as the complex processes by which living
organisms originated on earth and have been diversified and modified through sustained
changes in form and function "Evolution". Scientists, looking for an explanation to the
origin of man and other organisms created this evolutionism theory, which also presented
answers to the many asked questions dealing with similarities between species. Unlike the
theory of creation, which states that the complexity of life and different species can
only be explained in terms of a supernatural creator or god who placed life on earth, the
theory of evolution has a plethora of evidence proving it to be true "Creation". There are
several different types of observations that support the theory of organic evolution as an
explanation for the similarities and the differences among species. One such observation
is in the geologic record. The geologic record is the rock scheme found within the earth's
outer crust. By means of radioactive dating, the ages of rocks in many places on earth
have been determined. It is a timetable of the earth's geologic history. This combined
with the fossil record, another observation supporting the evolutionary hypothesis, has
produced an apparent sequence of life forms from most simple to most complex during the
history of the planet. Fossils are any remains or traces of a once-living organism, which
are formed by preservation, petrifaction, or sedimentation. Organisms can be preserved and
protected against decay by being trapped in amber, tar, or frozen in ice. The hard parts
of an organism, such as shells or bones, can be preserved when the flesh of an organism
has decayed away. In other cases, materials of a dead organism may be gradually washed
away and replaced by minerals from the water causing the organism to petrify, or harden.
Imprints, molds, or casts left by an organism after it is enclosed in sedimentary rock and
decomposed are also fossils, as well as footprints and tracks. The fossil record is the
timetable of fossils found in within the earth's geologic record. Since the upper layers
of sedimentary rocks are assumed to have been laid down over lower layers, the upper
layers are younger than those deeper into the earth. Therefore, fossils found within the
upper layers are also younger than those found within the lower layers. This combination
of geologic and fossil records shows the progression of species as time also progressed.
In reiterating the definition of evolution, we are reminded that gradual changes in one
life form's anatomy, cytology, embryology, or biochemistry could cause a new species to
originate. Similarities in these categories link species together and are therefore
studied to support evolutionism. In comparing anatomy, the structures of different
organisms often show unexpected similarities. Cell organelles, such as cell membranes,
ribosomes, and other structures found within cells, are also similar in organisms of all
kinds, showing that comparative cytology can also shows signs of evolution. When comparing
the embryos of different organisms, comparative embryology, similarities can be seen in
early stages of embryos that are completely different at maturity. Finally, comparative
biochemistry, which is the comparing of biochemical compounds, such as amino acids, can
also show similarities in species, reinforcing the idea of evolution. As curiosity rose
throughout much of the world, scientists began to question the existence of organisms and
why some are so alike in so many ways and so diverse as well. Several theories have been
proposed in the past to account for the diversity and similarity of species. One scientist
by the name of Lamarck proposed that changes in species occurred basically as the result
of a striving of organisms for improvement. One main point of this theory was use and
disuse. New organs appear in a species as a result of a need for them, and they increase
in size or effectiveness through repeated use. Organs not needed decrease in size or
strength because of disuse. A second idea included in his theory was the transmission of
acquired characteristics. This means that a trait acquired during the lifetime of an
organism, including improvements of existing traits, can be transmitted to its offspring.
Later in scientific history, it was Charles Darwin who came up with the most convincing
theories of adaptation and development. In 1859, he published The Origin of Species,
introducing the theory that species evolve from others, including man's development from
apes. Darwin proposed that evolution occurred as the result of natural selection. Natural
selection is the process by which environmental effects lead to varying degrees of
reproductive success among individuals of a population of organisms with different
characteristics and traits. It is the idea that organisms with favorable variations are
better able to survive and reproduce than organisms not well adapted "Natural Selection".
Overproduction is a main idea of Darwin's theory. He believes that more offspring are
produced than can survive, because of limitations in living space and food supply. He also
believes in competition, where individuals of each generation compete for available food
and opportunities to mate and reproduce. A third idea of Darwin's evolution theory is
variation, meaning some individuals are better fitted to survive than others, because of
variations in characteristics. Survival of the fittest was how he explained the fact that
individuals better fitted to survive are more likely to live longer and reproduce.
Darwin's idea of transmission of favorable characteristics modified the earlier idea
presented by Lamarck. Charles believed offspring of the fittest individuals would inherit
only the favorable variations that enabled their parents to survive and reproduce.
Explaining this idea, Charles Darwin stated, "Beneficial variations of all kinds will
thus, either occasionally or habitually, have been preserved, and injurious ones
eliminated" . In the end, Darwin expressed his idea on the evolution of species saying
that the accumulation of favorable variations will gradually lead to the appearance of new
species better adapted to their environment. Another scientist, DeVries, later added to
Darwin's theory that mutations were the source of new traits that permitted evolution to
occur. These scientists put together today's basis of thinking and questioning
evolutionary processes. Once these new scientific explanations were introduced into the
society, people began questioning not only animal origins, but also the beginnings of
mankind itself. Through years of research, experimentation, and applying the theories of
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