The Theory That Shook The World Essay, Research Paper

The Theory That Shook The World

Other than Mendellson and his studies with genetics,

Darwin has by far contributed the most to our modern science.

From his theories on variation of species to his explanation of

natural selection Charles Darwin has shocked the world by proving

the world older than previously thought and creatures not

immutable. In this present day these theories are as common

belief as a simple mathematical equation such as two plus two

equals four; but in the year eighteen hundred and fifty nine

Darwin not only risked his reputation with these far fetched

findings but also the risk of being excommunicated from the

church. Previous to Darwin the thought had been that the world

itself was only a few hundred years old and that all creatures

were made by God in those seven days as they lived exactly today

(Campbell p 421). Aside from past resistance, Darwin also comes

under scrutiny still today as missing fossils which are to have

been the bridge between a two familiar species are not yet found

(Hitching p 3). Whatever the reason of belief or disbelief in

Darwin’s theories, he astounded the scientific world as well as

the public and was able to convince many in the presence of a

misguided past belief. This fact alone makes him one of the most

important people of science ever.

Charles Darwin was born in Shrewsbury-Shropshire,

England on Feb 12, 1809 (GEA & RBi p 42). He was the fifth child

in a wealthy English family with a history of scientific

achievement with his paternal grandfather Erasmus Darwin who was

a physician and a savant in the eighteenth century (GEA & RBi p

42). As a young boy Darwin already showed signs of his love for

nature. When he was not reading about nature and its quirks he

was out in the forest looking for wild game , fish, and insects

(Campbell p 424). His father, although noting his son’s interest

in nature, felt that all the discoveries of the natural branch of

science had been accomplished so he sent his son to medical

school at Edinburgh instead (Bowler p 62). While Darwin was

there, he could not keep his mind on his medical studies and

decided to go and study at the University of Cambridge and become

a clergyman. It was here that he was to meet two people who

would change his future forever; Adams Sedgwick and John Stevens

Henslow. Out of these two, Henslow turned into his second father

and taught him to be meticulous in his observations of natural

phenomena (GEA & RBi p 42). Upon graduating in 1831, Henslow

suggested that he go on the Beagle as an unpaid naturalist on the

scientific expedition (GEA & RBi p 43). Darwin gladly took

Henslow’s advice and set out on his voyage to South America to

analyze and collect data that would later back up his

evolutionary theories (Campbell p 424).

Even as Darwin collected his data pertaining to what

would become his theory on natural selection, many pre-existing

views still had a hold on the scientific world as well as the

public. The earliest recorded were those of Plato and Aristotle.

Plato (427-347 BC) believed in two worlds; an illusionary which

was perceived only through our senses and a real world which was

ideal and eternal (Campbell p 422). Aristotle (384-322 BC), on

the other hand, believed in a “scala naturae” in which each being

has its own rung on a ladder which was permanent (Campbell p

422). Also, there were the present religious views that had to

be dealt with as well as the ancient ideals. At that time many

believed that animals and plants did not evolve because they were

made holy and immutable by God on those seven days (GEA & RBi p

43). A person who was widely respected and also took some

beliefs from Aristotle and present religion was Carolus Linnaeus

(1707-1778). He believed species immutable and later became

known as the father of modern taxonomy (Campbell p 422). Perhaps

the largest barrier Darwin had was to convince the present day

scientists of his findings in contrast to their pre-existing

theories. The most common of the time was the catatropist

theory. The definition of this theory was that “a violent and

sudden change in the earth” had destroyed all creatures and each

time this happened, God would come back down and recreate all the

life in a seperate seven days (Webster p 131). This theory in

itself seemed created for the soul purpose of covering up the

reason for fossils existing and misled thought of the species

being immutable (Campbell p 423).

After Darwin’s voyage on the Beagle, he had begun to

develop his own theory of evolution. His personal definition of

evolution was “in biology, the complex of processes by which

living organisms originated on earth and have been diversified

and modified through sustained changes in form and function” (JWV

p 20). In regards to his research he had not only found

evolution in the wild but in the domesticated sphere as well.

Darwin held that all related organisms descended from a common

ancestor and he found examples easily in common life (GEA & RBi p

43). One of these such examples were the domesticated pigeon.

Darwin studied the skeletal and the live forms of the pigeons he

had found. In doing so, he found them all to be related but for

a small change in their phenotype. Phenotype being defined as

follows “the actual appearance of an organism” (GEA & RBi-2 p

77). This small difference had been procured through the use of

breeding and mutation. Perhaps the most notable would be the

number of feathers in the fantail which ranged from twelve to

forty feathers (Darwin p 42). Another example Darwin found in

speciation by domesticated breeding were cows and horses. By the

definition of a gene pool, “large random assortment of genes that

may be rearranged”, the farmers were able to produce a better

breed of race horse or milk cow by breeding the best he had

together (JWV p 21). This sexual evolution was just seen by the

public as a way to produce the necessary end but Darwin held it

as important evidence of evolution accessible for all to witness.

And to back up this finding in the domesticated breeds as well as

the wild he came up with his variability within a species. The

definition to variability within a species held that 1) the

offspring resemble the parents , but were not identical and 2)

some differences in the parents were due solely to the

environment but were often inheritable (JWV p 20). These two

statements as well as the backup with clinical data helped to

show that his theory was correct.

Another area of variability was that of species in the

wild. Perhaps Darwin’s most famed findings to back his theory

are “Darwin’s finches”. During his voyage on the Beagle he had

observed thirteen different types of finches (Campbell p 425).

These finches were found on seperate Galapagos Islands. Here

each species of finch had at one time migrated to another island.

In doing so the founder effect had been put into action. The

founder effect being described as “when a few individuals of a

population migrate and form a new colony having only a small gene

pool causing a new species” (JWV p 23). Due to the diverse

surroundings and limited gene pool the thirteen species had

evolved from the original species that had migrated from the

mainland to the islands. Darwin also observed other animals on

these islands that were not found anywhere else in the world and

began to doubt the churches teaching that species were immutable

(Darwin p 29).

The most controversial of Darwin’s theory was that of

natural selection. The term evolution was so controversial even

Darwin did not use it but the phrase “origin of species” instead

(Darwin p 27). Even though he did not term it evolution his

views were definitely concrete and were laid out in a few simple

sentences. These were the reasons why natural selection was a

way of life and always had been. First, Darwin proposed that

food supply was too little to support the large population thus

eliminating those who were not strong enough to find food and

survive. Second, parents adapted to a certain environment well

would pass on favorable traits that would help the next

generation survive, those without the trait would not survive.

Third, each generation would become better adapted and if

remaining in the same environment would become more capable of

surviving. Finally, even with all the above working there were

also factors of mutation, genetic drift, and bottle neck theories

which contributed to the survival of the fittest (GEA & RBi p

43). Mutation being the most effective in changing a species had

four factors by itself: 1) size of a population, 2) the length of

a generation’s life span, 3) the degree to which the mutation was

favorable, and 4) the rate at which the same mutation appears in

descendants (JWV p 21). Although most mutations are fatal, they

are key in changing the genetic make up of an individual.

Genetic drift is described as when a species for some reason

begins to drift apart or come together to create a new specie or

species. This is typically seen in today’s fossil record when a

present species is related to an extinct animal. [see fig. 1]

Another of the traits of natural selection is the bottle neck

theory. Here a population has been destroyed to such an extent

that only a few survive. This limited population will recreate a

new species based on its extremely limited gene pool and have a

higher chance of carrying a fatal gene. All these factors

working together simultaneously create the phenomena of natural

selection.

Darwin was not going to publish his findings but was

forced to by a young man Alfred Russel Wallace who had come to

the same conclusion after twenty years had passed. Although both

scientists names were on the original copies of the Origin of

Species Wallace regarded Darwin as the soul author. Within a

year of writing, Darwin published what would be twenty years of

research in 1859. Although, thoroughly backed up with

painstaking research, it was still refereed to as “the book that

shook the world” and in its first day of sales had sold out (GEA

& RBi p 43). The immediate reaction in the science world was one

of disbelief. The leading scientists of the day said that Darwin

could not prove his hypothesis and the concept of variation could

not be proved. Darwin was to be doubted for the next seventy

years until the rediscovery of Mendel’s pea plant experiments

(GEA & RBi p 43). With these new findings on genetics, many

scientists would take in account Darwin’s work. Some of these

people were to be a German zoologist named Ernst Mayr, a botanist

G. Ledyard Stebbins, and paleontologist named George Simpson

(JWV p 21).