TAXONOMY
Introduction
One of the most
interesting fields of interest in the study of Biology is taxonomy. Although
there are other fields out
there such as ecology and embryology, taxonomy is
easy to comprehend, restricted to a small set of structural information, and
is good to know as reference. Taxonomy, also called systematics, is the study of the classification of all
living organisms. The
current method of taxonomy was started by Carolus Linnaeus (Carl von Linné)
which features organisms arranged into groups
within groups within groups, on and on until an
organism is defined within its own species or individual group. This orderly
classification
helps scientists in a number of ways. One is that it keeps
them clearly in sync with other scientists because of the existence of a
universal
system. It also helps scientists in identifying
evolutionary links between certain species.
How it works:
Originally, when
Linnaeus founded taxonomy, organisms were divided based on sole visible
physical characteristics.
Now they're
separated based on any unique and defining features mainly external physical
features and secondarily based on other
features such as feeding habits. Each organism is based on
binomial nomenclature. Each organism has two words to its name. The first name
is the genus and the second name is the species. For
example, humans are scientifically called Homo sapiens - genus Homo,
species sapiens.
The words that
make up the names for the individual groups of taxonomy are based on the Greek
or Latin language. This makes for a universal language
throughout the world. Otherwise an English scientist
mentioning a "cat" to a Chinese person would be misunderstood because
of language differences.
There are
international commissions out there that help filter and record an updated
listing of the classifications. Some names are
based on the equivalent characteristics of the
organism in Latin, or they could have no meaning at all and are just named
after their founder.
The Origins of
Taxonomy:
Classification has
been around on earth ever since people paid attention to organisms. One
primeval system that was developed
was based on "harmful" and "non-harmful"
organisms. Then, Aristotle was the first to form a useful system of
classification during
the 300s BCE. His was first based on whether the organism
had red blood or didn't have red blood. Then he subdivided organisms such as
plants by physical characteristics such as size and
features. This system is somewhat crude by today's standards, yet it lasted
over 2,000 years.
Eventually, as
communication improved and science had advanced to a reasonable point, modern
classification started to develop.
The most popular
founder was the Swedish naturalist Carolus Linnaeus
in the 1700s. He developed the system by which organisms are classified
based on the unique characteristics that they had.
He also invented the binomial nomenclature for naming. Linnaeus agreed with
scientists
that his work was somewhat crude, but its purpose and
general concepts were continually applied. Over time, as evolutionary studies
were
extrapolated, the classification system has become more
advanced showing different groups and links. And as time goes on,
classifications continue to change and are ever-growing.
Kingdom: This it the largest unit of classification.
Initially it was thought that there were only two kingdoms, plants and animals.
Eventually microscope
and other tools helped clarify the existence of other organisms. Now, there are
a total of 6 kingdoms.
Animalia – the largest with over 1 million named
species, insects, invertebrates, humans; Plantae - 350,000 species, trees, grass;
Fungi - 100,000
species, mushrooms, lichen; Protista -100,000
species, green, golden, brown, and red algae,
flagellates, diatoms, amoeba, slime moulds; Eubacteria - 10,000 species, blue-green algae or cyanobacteria; and Archaebacteria.
Phylum/Division:
The next most specific unit of
classification. This further divides the kingdom into 20 or so divisions based
on very
distinct and defining characteristics. For example,
within the Animal Kingdom, a major phylum is the chordates - animals with
notochords.
This includes humans,
fish, mammals, etc. Flowering plants are defined into the anthrophyta
division of the
Class: This further classifies the organism. It
separates them into categories that make them very similar in terms
of certain basic features.
For example the class Mammalia includes all animals that nurse their young, which
includes humans, cows, dolphins, etc. Another class would be Reptilia
which includes cold-blooded and scaled animals.
Order: Organisms of the same order are more similar
that that of the same class. A lot of obvious evolutionary connections can be
drawn from looking at the order; only a few features
separate the organisms as a breaking in the evolutionary chain. One example is
that within the class Mammalia,
carnivores are separated into the order Carnivora
while Insect-eaters are separated into the order
Insectivora. We belong to the order Primates.
Family: Even more narrowly defined the animals within
this taxon share a very close similarity. Most will
probably
have the same behaviour
patterns, feeding habits, and general functions. An example is the Cat Family (Felidaes) which all have
whiskers, sharp claws, and include animals such as
Lions and Cats.
Genus: This is the part that makes up the first word
of the binomial nomenclature of an organism. All the
organisms within their genus may look very similar to each other. And although
it is at most times not healthy, organisms of the same genus may breed with
each other.
Species: The most exclusive unit of classification is
the species. The species makes up all the organisms and their apparent
ancestors and descendants. Members of the species are much similar to their
parents and can freely breed with other members of the same species without
complication.