Student Name
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Mrs. Hosie
Biology
March 1, 2009
Thesis Paper
Astonishingly, ninety-nine percent of the genes of chimpanzees and humans are identical
(“Human Life from Evolution to Self-Evolution”). The previous certainty is just one of the
abundant pieces of evidence that help scientists in coming closer to determining the intricate
origins of life. The extremely controversial topic of human genesis has raised much debate for
centuries. Maybe humans are not meant to understand all of the details behind how life first
came to be. Nonetheless, advancements in technology have allowed scientists to come closer
than ever to the answers behind the countless number of questions about human origins. Based
on observations, research, and the laws of math and science, it can be concluded that evolution is
the process by which life came to be and evolved into the organisms living today.
Evolution can be defined as, “All the changes that have formed life on Earth from the
earliest beginnings to the diversity that characterizes it today” (Modern Biology 8). Evolution is
responsible for the formation of our whole universe, the development of life on earth, and the
changes in the first microorganisms to result in all living things today. A naturalist on the ship
H.M.S. Beagle for five years, a man by the name of Charles Darwin sparked interest among
people around the world about the theory of evolution in 1859. Darwin’s distinguished book
published in that year titled, On the Origin of Species by Means of Natural Selection, details
many pieces of evidence that support the theory of evolution. Over time, a profusion of points of
evidence have been identified (Modern Biology 286).
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The amount of evidence discovered that supports evolution today is extremely
multitudinous. Main points of indication include the fossil record, biogeography, embryology,
vestigial structures, comparative anatomy, comparative biochemistry, and cultural evolution.
One of the most convincing issues of evidence involves the fossil record. Fossils are traces of
long-dead organisms (Modern Biology 279). Many of the organisms preserved as fossils were
buried under many layers of mud or sand that later turned into rock. Researchers date fossils by
using various dating methods. Measuring the amounts of certain radioactive isotopes in a fossil is
a popular way scientists determine the age of fossils. Paleontologists have found enough fossils
to create a fairly complete record that chronicles the history of life on earth (Templeton 430).
The fossil record shoes the progression from the first simple organisms to the complex
organisms that live today. The fossil record indicates that quite a few species have become
extinct, and that species living today were not always in existence. Trilobites and sea scorpions
have completely disappeared in the fossil record. Evolutionary change and speciation are shown
in the fossil record also. No mammals lived before 250 million years ago, but many reptiles did
live back in that time period. Mammals first appeared in the fossil record around 200 million
years ago. Transitional forms have been found that existed in between the two time periods. The
transitional forms included animals that had characteristics of both mammals and reptiles. The
skeletal structures of the transitional forms resembled both modern mammals and reptiles. The
whole process of transition occurred quite gradually (Templeton 430). Measurements of
radioactive decay indicate that the Earth is billions of years old, allowing for the slow process of
evolution (Quammen 54).
The idea of biogeography is also an important factor in the fossil record and evolution.
Biogeography is the study of the geographical dispersal of fossils and living organisms. The
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fossil record indicates that new organisms arise in areas where similar forms already existed.
Modern armadillos closely resemble the now extinct glyptodont. Today, armadillos appear in
North and South America. In the past, glyptodonts lived in the Americas (Modern Biology 281).
Biogeographic evidence indicates that organisms evolve and go through evolution.
Embryology is also an aspect of science that points to evolution as the process of how life
first came about. Embryology is the study of the way organisms develop during the early stages
of life (Templeton 431). Development of embryos of organisms includes quite a few strange
events that can be explained by the evolution of the organism from other related species. For
example, most all vertebrate embryos are extremely alike when first developing (Modern
Biology 291). Many more examples of embryology have been discovered by scientists. Embryos
of mammals pass through various stages that resemble embryological stages of reptiles.
Interestingly, the larvae of moths, flies, and beetles resemble one another more than any of them
resemble their own parents. In fact, Darwin stated, “the embryo is the animal in its less modified
state and that state reveals the structure of its progenitor” (Quammen 1).
Evidence acquired from the research of vestigial structures is yet another reason to prove
why evolution is the answer to how life began. Vestigial structures are the useless remains of
organs that were at one point useful in an evolutionary ancestor. As an example, many species of
animals that live in caves are blind but still have eyes. These eyes evolved from ancestors that
had properly functioning eyes. Apparently, no pressure has been exerted on the cave-dwelling
organisms to lose the eyes. A cave dwelling organism’s fitness is not affected if its vision is
damaged, because eyes are useless in such a dark environment (Templeton 431). Yet another
example of vestigial structures involves the bone structure of whales. A collection of sperm
whales have bone-supported bumps and vestigial leg bones. The previous information indicates
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that whales most likely descended from an ancestor that lived on land. Many of the genes
required to produce hind legs have been unchanged in the genome of whales. The genes must be
slightly turned on, thus creating vestigial hind legs. Vestigial structures have even been located
in humans. The human tailbone is an example of a vestigial structure. Although it has no
apparent use or advantage in people, the tailbone is homologous to the tails of other vertebrate
species that are functional. The appearance of vestigial structures in organisms displays
evolutionary history due to the usually turned-off genes found in the organisms (Modern Biology
290).
The field of molecular biochemistry can also provide information that supports the idea
of evolution. The structures of molecules and amino acid sequences in all living organisms are
miraculously similar. Complex DNA and RNA constructions are found in all living organisms.
Cellular processes, such as the Krebs cycle, operate similarly in all living organisms. Atoms
rotate the same way in the same configuration in these processes (Lawton). The drastic
resemblance in the steps of such processes is a sign that there is a common ancestor to all living
things. Enzymes in mammals are virtually identical, and the same goes for enzymes in insects.
Hemoglobin is a protein in red blood cells. Scientists know many of the specific amino acids and
their sequences in hemoglobin molecules of numerous animals. As yet another example,
hemoglobin in animals and chlorophyll in plants are strikingly similar in relation to the processes
the molecules carry out (Lawton). Information that is shown as a result of studying molecular
biology and chemistry can help to verify any presumptions made from the fossil record about
evolution (Modern Biology 291).
Additionally, the aspect of predictability in the theory of evolution proves the idea
beyond a reasonable doubt. Scientists can actually predict elements of relationships between
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living organisms. If an organism was placed on an island, scientists today can make extremely
accurate predictions as to how the organism would eventually evolve to its new environment.
Darwin himself had made predictions about various animals and plants that he observed while on
his long voyage. Predictions have been made about the cicada bug’s appearance, behavior, and
locations as the bugs go through new life cycles. Based on heredity and evolution, scientists’
predictions about the bugs continue to be almost flawless. The characteristic of predictability that
evolution holds is a perfect point of evidence to prove its validity (Lawton).
Comparative anatomy can be referred to as the comparison of the makeup of structures in
different organisms. The study of comparative anatomy has contributed greatly to the
development of the theory of evolution. Comparisons can often lead to how evolution occurred
(Templeton 431). The beaks of the finches that Darwin observed on the Galapagos Islands
display this field of science. Each of the beaks on the birds of the different islands had just slight
differences. These differences occurred due to the fact that one original species of birds was split
up, and each new bird evolved to be able to survive best in its new environment. The close
similarity in the genetic codes and bone structure of the finches confirms that the birds
descended from a single ancestral species (Ridley 58). Homologous features are similar
properties that originated in an original shared ancestor. The forelimbs of the penguin, alligator,
bat, and human are extremely similar in skeletal structure and originate in the same structures in
embryos. The existence of homologous features in two different species demonstrates that the
species did share a recent common ancestor (Modern Biology 290).
Humans have also evolved culturally over time. This can be studied in relation to how
communication abilities have increased drastically along with the ability to express oneself.
Ideas and knowledge preserved in books has become more complex. Written language has grown
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immensely. The new computer technology wave coming in may even be assisting in the
evolution of humans. The study of the evolution of culture is just as important as the physical
evolution of organisms (“Human Life from Evolution to Self-Evolution”).
Critics of the theory of evolution may believe in creationism, the belief that the universe
and living organisms were created from certain acts of divine creation such as in biblical
accounts (“Voices for Creation”). Evolution provides a far better explanation as to how living
organisms came about. Although the fossil record is incomplete, various other forms of evidence
for evolution can take the place of the missing links of the fossil record. Scientists have
diligently researched the true mechanisms of evolution. Natural selection and mutations are
clearly the ways by which evolution occurs (Huxley 34). Although experiments can be done to
prove the theory of evolution, no experiments can be performed to prove the theory of
creationism. Because no experiment can be executed to prove creationism, creationists must
result to disproving evolution. Attempting to falsify a theory is often an extremely difficult task
to take on, especially in the case of evolution (Lawton).
Conclusions can be made based on observations, research, and the laws of math and
science that evolution is the process by which life came to be and evolved into the organisms
living today. Numerous amounts of evidence have been found to indicate that evolution is the
process by which living organisms came into existence and evolved into modern humans. Fossil
records, biogeography, embryology, vestigial structures, comparative anatomy, comparative
biochemistry, and cultural developments assist scientists in proving evolution to be true
(Templeton 430). Although humans are coming closer than ever to the solutions behind how life
was created, a countless number of questions and topics still remain unanswered and unexplored.
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Bibliography
“Human Life from Evolution to Self – Evolution.” 2005. Films for the Humanities and Sciences.
Princeton, NJ.
Huxley, Julian. Evolution in Action. New York, New York: Harper and Row Publishers, 1953.
Lawton, Richard. Professor Emeritus of Chemistry at The University of Michigan. Telephone
Interview. 28 February. 2009.
Modern Biology. Austin, TX: Holt, Rinehart, and Winston, 2002.
Quammen, David. “Darwin’s First Clues” National Geographic Feb. 2009: 44 – 55.
Quammen, David. “Was Darwin Wrong: No. The evidence for evolution is overwhelming.”
National Geographic November 2004. 1 March 2009.
<http://ngm.nationalgeographic.com/print/2004/11/darwin-wrong/quammen-text>.
Ridley, Matt. “Modern Darwin.” National Geographic Feb. 2009: 58 – 71.
Templeton, Alan R. “Evolution.” The World Book Encyclopedia. Volume 6. Chicago;
WorldBook, Inc. 2002.
“Voices for Creation.” NMU Public Broadcasting Service. Staff. 1997.