Download Good Evening Ladies and Gentlemen. Evolution is one of those

Good Evening Ladies and Gentlemen.
Evolution is one of those funny ideas that many people, while they may have a rough idea about
what it is about, often hold incorrect assumptions and beliefs as to what really goes on. It’s our role
tonight, to clear up these misconceptions, and guide you through the various theories that make up
the larger aspect of evolution. However, since this night will be primarily about evolution, it’s
important to get a clear and concise definition first. According to the ever trusty Wikipedia,
Evolution is the “change over time in the proportion of individual organisms differing in one or more
inherited traits”. Looking at that in more simple terms, evolution, and more specifically, Biological
evolution, is simply the change in a species over time. This can be relatively small changes, such as
the adaptation of a certain limb caused through a mutated genome, all the way to large scale
evolution, such as the development of a wholly different species evolving from common ancestors.
However, it is the reason and manner of which these “changes” occurs that interests us today, and
continues to be debated in the scientific and theological community.
Obviously, when most people think of evolution, they think Charles Darwin, with his theory of
natural selection, and his book On the Origins of the Species that caused such uproar when it was
released. And whilst Darwin can correctly be called one of the founding fathers of evolution, it is
important to remember both the earlier pioneers in this relatively new science, and also the modern
day scientists, that have continued to refine and develop the theory since then.
So tonight we start with one of the pioneering scientists for the development of the theory of
evolution: Jean-Baptiste Lamarck. In the years before this, the widely accepted belief was that of
creationism, that of the “Divine Being” creating each species, and life continuing from there.
However, in his book Philosophie Zoologique (and if you would please excuse my French) released
1809, Lamarck recognised various factors which would pave the way for later scientists, such as
Darwin, to help explain the origins of the species.
Lamarck believed that an innate and supernatural life force drove species to become more complex
over time, advancing up a linear ladder of complexity. He believed that this supernatural “force” was
the driving aspect of evolution. Lamarck’s theory also proposed that organisms passed on traits and
adaptations they had acquired during their lifetime, known as acquired traits, to their offspring. For
example, using the example of a giraffe, Lamarck believed that early in their development, giraffes
might have had relatively normal sized necks. However, if giraffes repeatedly stretched their necks in
order to reach leaves high in the trees, their necks would eventually lengthen. These giraffes would
then have offspring with these slightly longer necks, and this cycle would continue until giraffes
appear as they are today. His theory could also be applied to the disuse of certain characteristics of
organisms. For example, with an emu; according to Lamarck’s theory, these birds may have once
been capable of flight, but the continued disuse of their wings, this has led them to become
flightless. So his theory was based on the idea that through the use or disuse of a certain
characteristics, organisms were able to improve or adapt themselves to better fit the environment.
However, Lamarck’s belief in an “innate life force”, continued to fuel debate within the theological
and scientific communities. It was only many years later that Lamarck’s theory was significantly
questioned, and this was led by the observations of a scientist named Charles Darwin. Building on
Lamarck’s works, Darwin released his On the Origins of the Species in 1859. Darwin removed the idea
of a supernatural life force within his work, and instead introduced his theory of “natural selection”,
whereby those organisms with more favourable adaptations were more likely to survive in the wild,
and also, controversially, believed that all life was in fact descended from a common ancestor.
Darwin proposed that organisms passed on random genetic mutations, as well as acquired
characteristics, almost blending his own ideas with Lamarck’s.
At the time in which Darwin released his works, the theory of evolution was widely supported within
the scientific community. However, what remained to be debated was the force driving evolution.
Many critics at the time were unhappy with Darwin’s reasoning that seemingly random mutations
would eventually culminate in a favourable adaptation, saying that it could not account for the
amount of complexity and diversity within biological life today. In addition, at the time Darwin
released his works, he was not entirely sure as to the method upon which organisms passed their
mutations on, and it was only decades later that this questioned was answered.
However, it is important to remember that Darwin’s theory was not entirely correct. Like Lamarck,
Darwin also incorrectly believed that organisms also passed on acquired traits to their offspring. This
idea has been proven incorrect today, and the actual science of this phenomena will be explained be
one of my fellow team members.
It was only later in the 1900’s, when the American evolutionary biologist, Thomas Hunt Morgan,
discovered the fact that that genes were carried on chromosomes, and that it was mutations of this
genetic material which resulted in the evolution, that Darwin’s theories reached such importance.
So whilst the development of the theory of evolution no doubt had its roots in the inquisitive minds
of scientists in the 1800’s ---- (Introduction for next speaker’s topic)