Stacey Barlow        What is a species?        050139246

What is a species?

Species is a Latin word meaning ‘kind’ or ‘appearance.’” (Campbell and Reece, 2005, p.473).   However, clarifying what actually constitutes a species is controversial, as Biologists cannot agree on a specific definition of the word. Species is a term used by humans in attempt to place different ‘kinds’ of organisms into distinct groups using taxonomy – biological classification.  A scientific name in the form of a binomial nomenclature is used to describe these groups.  It is always written in italics with the capitalised Latin genus name followed by the species name.  Species, therefore, is a fundamental category in taxonomy and important in the scientific naming of organisms.  It is therefore essential for us to have a proper understanding of species. However, as a consequence of Biologists being divided in opinion on the nature of species, several concepts have been proposed to define the term. Therefore the answer to the question ‘what is a species?’ differs depending on which species concept is applied.

The biological species concept (BSC) is the most frequently used and widely accepted definition of species.  This concept was originally proposed in 1942 by biologist Ernst Mayr.  Ernst Mayr stated that “species are groups of interbreeding natural populations that are reproductively isolated from other such groups.”  (Ernst, 1963 cited in Ridley, 2004. pg. 351) In other words the individuals of a species are determined by their potential of being reproductively compatible; “This biological species concept defines a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are unable to produce viable, fertile offspring with members of other populations.” (Campbell and Reece, 2005, p.473).

Join now!

Despite the BSC being a commonly universal definition of species, there are some problems with the concept.  Firstly, this concept can only be applied to sexual reproductive organisms and therefore can not be applied to asexual organisms or fossilised extinct organisms:

"Where we have sexual reproduction a species can be objectively defined as a group of organisms which reproduce sexually amongst themselves but don't reproduce with members of other species.

Where we don't have sexual reproduction - as in asexual species, or in fossils where we have no idea of how they reproduced - then there is ...

This is a preview of the whole essay

Here's what a teacher thought of this essay

Avatar

Overall this is a well thought out essay. It has a very clear and logical structure, and covers each of the necessary points. Ideally it would include a few more biological examples, and a slightly deeper thought of how these philosophical concepts actually apply to research science. This, and the heavy reliance on quoting others' work prevent this from being a first class essay. If a definition is very specific then it can be quoted, and of course if something is paraphrased from a single source it should be referenced. But in several places this essay just quotes large bodies of text with no effort to understand or explain them. The student may have read the text and internalised it, but without attempting to put it into her own words, we cannot be sure that she truly grasps the significance. At my (Russell Group) university, this would score 4 stars.