FREE ESSAY ON EVOLUTION THROUGH NATURAL SELECTION

EVOLUTION THROUGH NATURAL SELECTION

Children often play a game called telephone, where one child whispers a statement into
another child's ear, and the statement is passed on to other children; at the end of the
game the last child will repeat the statement that was told to him or her. The majority
of the time, the statement said would be completely different than the original one. This
is an example of evolution through natural selection; where somewhere along the life span
of the statement, it was modified, and the modified statement was passed on to form a new
statement. 
Charles Darwin stated that, "individuals are the unit of selection; the struggle for
existence is a matter among individuals." In this statement Darwin is referring to
natural selection. Natural selection is defined as the differential contribution of
offspring resulting from variations in heritable traits. As a result of natural
selection, certain individuals in a given population produce certain traits that others
do not. Natural selection is the only agent that adapts organisms to their environment;
if a species cannot adapt to their environment, eventually they will be extinct.
In my visit to the American Museum of Natural History (AMNH), I observed many interesting
things concerning the issue on evolution and natural selection. An example of
evolutionism I saw in the AMNH was the Hall of Human Biology and Evolution. This hall
concentrated on human evolution and how certain traits arose through successful
generation—such as the change in the skeletal system as a result of walking
upright. Fossils of Australopithecus afarensis, which is believed to be the earliest
human relative, are dated back nearly 4 million years.
The Hall of the Vertebrate Origins is another exhibit that shows evidence of
evolutionism. The purpose of this hall is to show that all vertebrates had a common
ancestor. That common ancestor had a brain case and a backbone. As time progressed, the
vertebrates developed limbs that were supported by the backbone, and had watertight
eggs.
The Hall of Saurischian Dinosaurs and the Hall of Ornithischian Dinosaurs are more
examples of evolution within vertebrates. However, these two halls do not have much in
common with our line of ancestry except for the fact that a backbone and brain case are
present; any other things in common with our lineage are but minor details. That is why
the AMNH has another hall called Mammals and Extinct Relatives.
The hall, Mammals and Extinct Relatives, is devoted to showing how all mammals evolved
from the earliest forms of vertebrates. A big evolutionary change that separates mammals
from other forms of animals is the development of the placenta and the formation of the
middle ear. 
The hall that I believe to be the most interesting of all halls in the AMNH, is the Hall
of Biodiversity. In this hall we can see a large spectrum of life from the broad
"Kingdom" to the specific "Species" is found in this part of the museum. The amount of
information that one can obtain from just this hall alone is overwhelming. From the
simple far left (true bacteria) to the complex far right of the hall shows us a great
difference in species as well as many similarities. But more importantly, the hall shows
that many of the more complex living species today have evolved from another living or
extinct species in the past. Furthermore, those living/extinct species in the past
originated from another more ancient species, and so on.
Natural selection is a nonrandom event and is a process that happens over large periods
of time. The offspring that carry a certain trait that is favored due to a certain
environment will be carried on more successfully by their offspring. Due to this process
change, even if it is minute, will occur over a small number of generations. If such
selection continues to occur more complex forms of a simpler body plan will arise.