Hi!

You might have seen these, no idea to what extant these are useful, your question was very interesting, out of curiosity when I searched many articles appeared, I just picked some.

The Effect of Essentialism on Taxonomy--Two Thousand Years of Stasis(I)

http://www.explorelifeonearth.org/cursos/Hull1965I.pdf

The reality of taxonomic change

http://dare.uva.nl/document/17546

Philosophically speaking, how many species concepts are

there?

http://philpapers.org/archive/WILPSH.1.pdf

Natural kinds and Biological taxa

http://www.philoscience.unibe.ch/documents/kursarchiv/HS07/Dupre2002.pdf

The ontology of biological taxa

http://bioinformatics.oxfordjournals.org/content/24/13/i313.full.pdf+html

The Biological Reality of Species: Gene Flow, Selection, and collective evolution

http://www3.botany.ubc.ca/rieseberglab/loren%20pubs/2001%20taxon%20Rieseberg%20and%20Burke.pdf

Species Are Not Uniquely Real Biological Entities

http://ib.berkeley.edu/courses/ib200b/readings/Mishler_2010_Arp_Ayala_species_arent_uniquely_real.pdf

Dr. Ramadevi,

Thank you so much!

Please, try to look through the paper "Life origination hydrate Hypothesis (LOH-Hypothesis) : Original Approaches to Solution of the problem" and, may by, some works cited there. I believe, this paper is in context of your question, though it gives no direct answer to your question. This paper is available by free in the Global journal of science frontier research; Physics and space sciences, v.12, issue 6, version 1.0, year 2012, pp 1-36 (US) and it is download here at ResearchGate.

Perhaps, I should give the author's names of the paper mentioned by me: Victor Ostrovskii and Elena Kadyshevich, Karpov Institute of Pyysical Chemistry and Obukhov Institute of Atmospheric Physics, Moscow.

The fact is that, when having a wide multitude of items, any resourceful person can straddle them by any parameter, for example, by their complexity; may be, this sequence will have some blanks.

The question of the reality of higher taxa - and indeed of species as such - are classical issues in the philosophy of science. You will find treatments of such issues in works by, for instance, Elliot Sober, if I remember correctly. In the "old days" (when I mostly read about such issues, some 25 years ago...), it seemed that many thought species real but higher taxa only as tools for "making order of nature". With modern molecular systematics, relationships between organisms are now far better known but rarely fit nicely into groups matching concepts like genera, families, etc. On the other hand, clades are real enough - groups of organisms descending from a common ancestor. What we call such clades is probably a semantic rather than a scientific question.

Dears Victor and Trond,

Thank you very much for interesting information!

Olivier Rieppel has discussed this problem at some length in a number of papers. Basically, if you believe that species are metaphysical individuals (real things that exist in nature rather than concepts), then so is any other monophyletic taxon.

Rieppel, O. 1986. Species are individuals: a review and critique of the argument. In M. K. Hecht, B. Wallace and G. T. Prance (eds), Evolutionary Biology, vol. 20. Plenum Press, New York, pp. 283-317.

Rieppel, O. 2005. Monophyly, paraphyly, and natural kinds. Biol. & Philos. 20: 465-487.

Rieppel, O. 2007. Species: kinds of individuals or individuals of a kind. Cladistics 23: 373-384.

Rieppel, O. 2011. Species are individuals - the German tradition. Cladistics 27: 629-645.

Dear Andrew, thank you very much!

I've argued at length that genera and higher taxa can be evolutionary units in the sense that analytically they can be seen to generate descendant taxa. Analytically in terms of stem-thinking not sister-group thinking. See Zander, R. H. 2013. A Framework for Post-Phylogenetic Systematics (available inexpensively on Amazon). I also discuss scenarios in which this might happen mechanistically.