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What is the concept taxonomy?

Taxonomy is part of a larger division of biology known as systematics. Taxonomy is that branch of biology dealing with the identification and naming of organisms. Taxonomist do this to bring order to the complexity of organisms that live on this planet. Having such an ordered system helps us to better understand these organisms and our environment, find unifying concepts and create new hypotheses.

Video showing an example why identification of species is important.


It is very important to understand that the systems in which we order organisms are never perfect. They are only models that help us grasp the sheer diversity of life and are constantly subject to change.

Who invented the discipline of taxonomy?

The ancient Greek philosopher Aristotle apparently began the discussion on taxonomy. British naturalist John Ray is credited with revising the concept of naming and describing organisms. During the 1700s, Swedish botanist Carl Linnaeus classified all then-known organisms into a system that we still use today. With that he revolutionized taxonomy. Linnaeus introduced a binomial naming system for animal and plants species, which means that he gave every plant and animal species a "first" and a "second name". For instance the correct latin name of people is Homo sapiens. No other organism on this planted except us is called Homo sapiens. This was a major contribution to science, because before that, organisms had long descriptions that made communication among scientist speaking different languages very difficult.

Image of Carl Linnaeus.

Portrait of Carl Linnaeus.

In addition, Linnaeus created a hierarchical classification system based on the premise that the species was the smallest unit, and that each species is nested within a higher category. Because this was such an important contribution to the field, Linnaeus is also called the father of modern taxonomy.

After Linnaeus, other taxonomists worked on the classification system. Robert Whittaker in 1969 proposed five kingdoms (Plantae, Animalia, Fungi, Protista, and Monera) where all living organisms were grouped in.

Other schemes involving an even greater number of kingdoms have lately been proposed. Recent studies suggest that three domains be employed: Archaea, Bacteria, and Eukarya.

The current taxonomic scheme looks like this:

Image of the taxonomy pyramid.


What happens when a new species is discovered?

When scientists find a new species, they study the characteristics of this organism and try to find out where in the classification system it belongs to (by the use of different methods of systematics, see Leaf: What is systematics?.

In order to name that new organism, taxonomist follow a set of rules, the International Code of Botanical Nomenclature (ICBN) for plants, the International Code of Zoological Nomenclature (ICZN) for animals.

Some general rules for nomenclature:

  • All taxa must belong to a higher taxonomic group. Often a newly discovered organism is the sole species in a single genus, within a single family...etc.
  • The first name to be validly and effectively published has priority. This rule has caused numerous name changes, especially with fossil organisms: Brontosaurus is invalid, and the correct name for the big sauropod dinosaur is Apatosaurus, Eohippus (the tiny "dawn horse") is invalid and should be referred to as Hyracotherium. Sometime, however, names can be conserved if a group of systematists agrees.
  • All taxa must have an author. When you see a scientific name such as Homo sapiens L., the L. stands for Linneus, who first described and named that organism. Most scientists must have their names spelled out, for example Libopollis jarzenii Farabee et al. (an interesting fossil pollen type I stumbled across a very long time ago!).


More on nomenclature in this video:
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References:

  1. http://www.emc.maricopa.edu/faculty/farabee/biobk/biobooktoc.html



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Page last modified on Wednesday 02 of September, 2015 09:37:23 EDT

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