Evolution: The Theories of Charles Darwin and Evidence Supporting Them

Running head: EVOLUTION
Evolution
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1EVOLUTION
Evolution is a process by which changes in heritable character in population over the
generations. This critical theory of biology postulates the changes in the every living thing from
their ancestors (Kluger ;706). In century 19, the naturalist and biologist of England Charles
Darwin first claimed that every organism exists in population evolved due to the process of
evolution and come up with substantial pieces of evidence that explained by theory. Therefore,
this essay focuses on theories proposed by Charles Darwin and evidence that support those
theories. This essay will also illustrate the proofs of Darwin’s theory, the interaction between
human and environment, population size, global diseases that concern human being and other
environmental factors.
Darwin’s theory of evolution widely accepted worldwide explains that all organisms
exist in the earth are related to each other by common ancestors. Over the time, all living
organism diverged from ancestors due to changes in environments or genetic modifications.
Charles Darwin proposed a mechanism behind by evolution named as ‘Natural selection’ that
found in the book origin of species” (Seehausen et al.; 176). This theory explains that natural
selection is a process of nature where only organisms those adapt best in natural environment
tend to survive and transmits those specific adaptation traits to their next successive generations
(Richards; 220). Over the time, those are unable to adapt to situation extinct over the period.
Darwin proposed this theory by observing similar but non-identical species of finches on an
island. This theory explains three crucial facts such as traits are often heritable from ancestors,
Organism capable of producing offspring more than the environment can support, offspring
differ in their genetical characters (Smith; 418). The prime source of the evolution was first
discovered by palaeontologist that know n as ‘fossils’, which shows that many extinct organisms
are very much different from any living being live in the earth (Bellwood et al.; 60). According

2EVOLUTION
to this fossils record, the First vertebrate with backbone appeared approximately 400million ago
whereas the first mammal appeared less than 200 million ago (Wilson). It also shows the
successful transition of one organism to another through adaptation. The perfect example of such
adjustment is the long neck of a giraffe. On the other hand, due to lack of adaptation ,dinosaur
extinct over the time. Molecular biology reveals that common genetic sequences are identical for
all living things. One of the most prominent evidence that confirms every aspect of evolution is
genetic material of organisms DNA. The amount of information of development that stored in
DNA along with protein is virtually unlimited. Due to new technologies, it is possible for the
scientist to decipher the genetic code that resides in DNA ( Massey ). It reveals that four simple
bases arranged in a countless way to form the genetic codes of every living organism in the earth.
This process of evolution also provided the scientist to understand the similarity of DNA
between two related individual in species, which confirms that siblings have higher similarity in
genetic material, which acquired from parents where cousins inherited half of DNA.
Resemblance also found in non-identical species such as 146 amino acids found in a beta chain
of hemoglobin, out of which 138 amino acids are identical to human where dogs have 114 amino
acids nearly similar of human hemoglobin. This observation further proves that social share more
genetic resemblance with common ancestors of rhesus monkey than dogs.
The interaction between environment and human changed the direction of evolution,
which confirms that even if heredity is a critical factor for successive transmission of adaptation
traits, environment also manipulates the direction evolution. All features of the living organism
that exists in the globe are solely depending on both heredity and environmental factors.
Phenylketonuria (PKU) is one such example of the interaction between environment and genetic.
In PKU, mental retardation observed in individuals due to toxin effect of the ill breakdown of