Evolution Essay: Exploring Darwin's Theories and Supporting Evidence

This essay provides a comprehensive overview of Darwin's theory of evolution, focusing on the core principles of natural selection and the evidence that supports it. It discusses how traits are heritable, the overproduction of offspring, and genetic variation. The essay explores fossil records, molecular biology, and the role of DNA in confirming evolutionary relationships. Furthermore, it examines the interaction between humans and the environment, including the influence of environmental factors on genetic traits, such as Phenylketonuria (PKU), and the impact of mutation and genetic drift. The essay also addresses the effects of population size and the depletion of natural resources. Finally, it delves into the impact of global diseases, such as heart disease, stroke, and respiratory illnesses, on the evolution of species. The essay concludes by emphasizing the importance of adaptation for survival in a changing world.

Running head: EVOLUTION
Evolution
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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

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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

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amino acid phenylalanine by the defective enzyme. Therefore, a single gene controls the PKU
(Jahja et al.).However, the expression of this gene depends on environmental factors that decide
the development of PKU. Mutation is one of the raw materials of genetic variation. Every
genetic feature that resides within individual results from mutation occurred by genes or
environment. Most of the mutation that observed in creatures is a point or single gene mutation
that leads to new genetic variation. Genetic drifts are also remarkable in influencing the
population. Genetic drifts defined as the random fluctuation of genes that variable in population
increases or decrease over a period (Lynch et al.; 710).It observed in a small population where
the frequency of giving rise to allele is low. Therefore, either over time these rare allele lost or it
exists as the only allele that resides in a particular locus in a population. Consequently, it hinders
the chances of biodiversity. However, population size also massively changes the process of
evolution. In the recent era, the current population of the world is 7,632,819,325, where the
changes of numerical are unpredicted (Tricarico; 420 ). The exponential increase of population
size is a prime concern in reserving natural sources and remarkable traits. High population size
demands top resources for living quality life. Due to random enlargement of populations’ size, a
significant amount of natural causes depleted which giving rise to struggle for resources in every
layer of the food chain. Subsequently, creatures, those have excellent adaptation capabilities in
environment where resources are depleting survive and receive additional advantages from
nature due to few inherited genetic traits. Therefore, species evolved time to time by the
interaction of environment and genes.
As the population continues to grow worldwide, every individual of food chain harassing
the natural resources to fulfill their primary need. Few anthropogenic actions destabilize the
economic balance of the earth. The consequences involve global climate changes, the frequency

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of occurring drought due to global warming. Apart from these environmental factors, few global
diseases such as transmissible infectious disease and non-transmissible destabilize the genetic
traits and economy of the globe. World health organization enlisted few deadly illnesses that
significantly increase the death rate and decreases the chances of reserving unique genetic
characters. The first deadly disease is ischemic heart injury where blood vessels that pump blood
to the heart become narrowed. Approximately, 8.8 million people died from this heart disease
(Fihn et al.; 1930). The second deadly disease is stroke where deprivation of oxygen blocked the
brain. Nearly, 6.2 million died from stroke every year (Kernan et al.). Third deadly diseases are
a lower respiratory disease such as influenza, pneumonia and tuberculosis that arises through
Pathogenic microorganism where 3.2 million people died unexpectedly even after proper
medication. A fourth deadly disease that destabilises the quality of life is chronic obstructive
pulmonary disease, which is progressive lung disease where breathing becomes difficult
(Vogelmeier et al.; 560 ). Last most common condition that observed worldwide is diabetes that
increases the morbidity level (Powers et al; 50). Therefore, over the decade deadly diseases
significantly influence the journey of all living organism.
Hence, it can be concluded that the concept of evolution proposed by Darwin is the prime
cause of differences in a unique genetic trait that acquired over the time. It is a unique process
joins all the living being on the earth. Over the time, according to natural selection, only those
species survived who has additional advantages of nature. Therefore, to survive globe adaptation
is the primary criteria for transmitting unique genes to offspring.

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