Animal Taxonomy
How Do Animals Get Scientific Names?
In the 18th century a scientist called Carl Linnaeus began a revolution in the way we name living organisms, dividing everything into three Kingdoms; animals, plants and minerals.
The Linneaus system also organised living organisms into a series of different levels of classification, which he called ranks, that resulted in a tree like structure with the
- Kingdom at the base then diverging through the different ranks:
- The Kingdom of animals was divided into Classes such a fish, mammals or birds.
- Classes were divided into Orders
- Orders into Families
- Families into Genera
- Genera into Species
Therefore, each species had a binomial name consisting of its Generic name with a capital and specific name. ie, domestic cat Felis (happy) catus (cat). Note: Scientific names are preferably italicised, but may be underlined. Each species could also
Linneaus system of classifying was based on observations of organism’s similarity in morphology, such as hair, scales, or feathers, or wings, legs and feet or fins, or bone structure, and somewhat on habitat. Linneaus system of classification did not assume evolutionary theory or genetics, as these sciences were still not founded. However, the ranks were highly suggestive of a progressive development of species from a common ancestor but this idea was heretical to Christian religions at the time.
However, new scientific knowledge placed further demands on taxonomy to reconcile the nature of species. This knowledge was partly developed through palaeontology showing that organisms in the fossil record showed development in complexity as the age of fossils became more recent. This observation combined with the observation that organisms produce far more progeny than needed to maintain populations, and that these progeny were selected by natural mortality to eventually reproduce consolidated into evolutionary theory as finally published by Charles Darwin 1859 book On the Origin of Species.
Gregor Mendel (1822-1884) a Christian monk, in isolation, established the principles of heredity or inherited traits. However, his work was not re-discovered until the early 20th Century and created the science of modern genetics eventually resulting from 1930s to the 1950s in a broad consensus in which natural selection was the basic mechanism of evolution.
As time progressed and evolutionary theory became accepted a general rule; if organisms interbred between each other, they would be considered to be in the same species. There are exceptions called hybrids that are uncommon in nature but frequently used in industry particularly to produce domestic plant varieties.
With the development of modern genetics to determine phylogeny and electron microscopes to reveal micro-structure we can now classify species with greater certainty. The most powerful of these are regions of ribonucleic acid in mitochondrion, the energy factories of cells, that mostly mutate at random. Therefore, the difference in these between species tells us how related the species are and even when they diverged from a common ancestor.
The assessment of individual genes gives even more power to ascertaining evolutionary theory and currently teams are working globally to sequence the whole DNA of thousands of species to further the Tree of Life.
Taxonomy at the species level has previously been a “messy” field of science, with many species receiving multiple names, type specimens being lost, ambiguous and inept descriptions of species, and through scientific rivalry in being the first to name species. At the species level and in higher ranks there have been numerous renamings and re-rankings.
Modern Science has Changed Taxonomy
With the use of genetics to determine phylogeny, increasing detailed knowledge of morphology and knowledge of the fossil record and geology; our understanding of the evolution of animal species is much more informed than in Linnaeus’ time At extremes some argue strongly for a “rank free” system of classification but the vast majority still broadly support and use the use of Linnaeus’ system. Nevertheless, scientists currently generally consider that the higher level ranks, above Order, consist of Domains Bacteria and Archaea (no distinct nucleus, bacteria etc), and the Eucaryota (distinct nucleus), which are for instance divided into the Kingdoms of animals, plants, protozoa and fungi.
The International Commission for Zoological Nomenclature acts as a global authority for managing the naming of animals internationally. They produce & manage any changes to an International Code for Zoological Nomenclature; which provides a central reference that all animal taxonomists can refer to. Because of the low cost of genetic analysis the description of a new species now must include a phylogenetic genetic analysis.
As we learn more about animals (and plants); and understand the genetic, chemical and anatomical similarities and differences in ever increasing detail, our perception of the relationships between different organisms continues to grow. The current avalanche of knowledge has resulted in vibrant and sometimes heated debate among scientific schools of thought, especially in terms of higher classification (ranks), and generally more certainty and ironically sometimes uncertainty at the species level.
[19/04/2024 12:50:02]