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, the beloved Aristotle
was the first to form a useful system of
classification during the 300s BC. 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 it's 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.
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 Carlous
Linnaeus which features organisms arranged into
groups within groups, within groups, on and on until
an organism is defined within it's 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 Linnaues 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. This is in which
an organism has two words to it's name. The first
name is the genus and the second name is the specie.
For example, humans are scientifically called
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.
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
5 kingdoms. Animalia - the largest with over 1
million named species, fish, humans; Plantae -
350,000 species, trees, grass; Fungi - 100,000
species, mushrooms, lichen; Protista - 100,000
species, green, golden, brown, and red algae,
flagellates; Monera - 10,000 species, blue-green
algae or cyanobacteria.
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 division is the chordates
that are animals with notochords. This includes
humans, fish, mammals, etc. Flowering plants are
defined into the antrophyta division of the Plant
Kingdom.
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
breast-feed, 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.
Family: Even more specific, the animals within this
share a very close similarity between each other.
Most will probably have the same behavior 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 specific 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 much
complication.
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