Biosystematics, and types of taxonomy

1.Definition and basic concepts of Biosystematics, , Historical perspectives of Biosystematics and Taxonomy, Stages of taxonomic procedures-alpha taxonomy, Beta taxonomy and Gamma taxonomy,
Neo taxonomy.

1. Biosystematics, and types of taxonomy By Datta Ashok Nalle

2. Unit I: Biosystematics, and types of taxonomy 1.Definition and basic concepts of Biosystematics, , Historical perspectives of Biosystematics and Taxonomy, Stages of taxonomic procedures-alpha taxonomy, Beta taxonomy and Gamma taxonomy, Neo taxonomy . ( SLIDE 3 TO 17 ) Approaches/Trends in taxonomy-embryological, ecological, ethological, cytological, Biochemical, and numerical approaches in taxonomy Significance/Importance of Taxonomy in – biodiversity and conservation, research, medicine,agriculture and pest management, and fisheries. BY.DATTA A NALLE 2

3. Definition of Taxonomy: The term taxonomy is derived from two Greek words – taxis meaning arrangement, and nomos meaning law. It was first proposed in 1813 by A.P. de Candolle (a professor of Montpellier University in France) in its French form, for the theory of plant classi­fication.  “Taxonomy is the theoretical study of classification, including its bases, principles, procedures and rules”.  According to Mayr (1982),  “Taxonomy is the theory and practice of classifying organisms” . Taxonomy is thus an information system comprising of classification, nomenclature, descriptions and identification. According to Christoffersen (1995 ), taxonomy has become the most basic activity in biology, dealing exclusively with the discovery, ordering and communication of patterns of biological taxa . It, however, leans heavily on systematics for its concepts. BY.DATTA A NALLE 3

4. Taxonomy is the study of scientific classification, in particular the classification of living organisms according to their natural relationships. Taxonomy's first father was the philosopher  Aristotle  (384-322 BC), sometimes called the "father of science." It was Aristotle who first introduced the two key concepts of taxonomy as we practice it today: classification of oranisms by type and binomial definition. Aristotle was the first to attempt to classify all the kinds of animals in his  History of Animals  ( Historia Animalium  in Latin). He grouped the types of creatures according to their similarities: animals with blood and animals without blood, animals that live on water and animals that live on land. Aristotle's view of life was hierarchical. He assumed that creatures could be grouped in order from lowest to highest, with the human species being the highest. Subsequent commentators on Aristotle interpreted this as a "ladder of nature" ( scala naturae ) or a "Great Chain of Being," but these were not Aristotle's terms. His system of classification was not evolutionary, and the various species on the ladder had no specific genetic relationship to each other. Aristotle regarded the essence of species as fixed and unchanging, and this view persisted for the next two thousand years. BY.DATTA A NALLE 4

5. His other innovation was binomial definition. "Binomial" means "two names," and according to this system each kind of organism can be defined by the two names of its "genus and difference." The word "genus" comes from the Greek root for "birth," and among its meanings are "family" and "race.“ Aristotle's notion of definition was to place every object in a family and then to differentiate it from the other members of that family by some unique characteristic. He defined humans, for example, as the "rational animal." This, according to Aristotelian thought, defines the essence of what it is to be human, as opposed to such pseudo-definitions as "featherless biped. BY.DATTA A NALLE 5

6. Andrea Cesalpino  (1519-1603) was an Italian physician who created one of the first new systems of classifying plants since the time of Aristotle. He was a professor of  materia   medica , the study of the preparation of medicines from plants, at the University of Pisa, and was also in charge of the university's botanical garden. There, he wrote a series of works titled  On Plants  ( De Plantis ), detailing his system of classification. While his work was in large part based on the work of Aristotle and his successors, his innovation in basing his system of classifying plants on the basis of the structure of their fruits and seeds influenced subsequent scientists such as Linnaeus. Andrea Cesalpino   (1519-1603) BY.DATTA A NALLE 6

7. Carl ( Carolus ) Linnaeus  (1707-1778) was born, there were many systems of botanical classification in use, with new plants constantly being discovered and named. This, in fact, was the problem — there were too many inconsistent systems, and the same plant might have several different scientific names, according to different methods of classification. During his childhood, Linnaeus was so fond of collecting plants that he was known as "the little botanist." He later became a physician, as so many other early taxonomists did, but returned to botany as his primary study. He published his most innovative work as a young man in 1735.  The System of Nature  ( Systema Naturae ) is notable for an overall framework of classification that organized all plants and animals from the level of kingdoms all the way down to species. The full subtitle of its tenth edition was:  System of nature through the three kingdoms of nature, according to classes, orders, genera and species, with characteristics, differences, synonyms, places.  This system of classification, although greatly modified, is essentially the one we use today. BY.DATTA A NALLE 7

8. BY.DATTA A NALLE 8 THE BOOK WRITTEN BY Carolus Linnaeus 

9. Among biologists the Linnaean system of binomial  nomenclature , created by Swedish naturalist   Carolus Linnaeus  in the 1750s, is internationally accepted . BY.DATTA A NALLE 9

10. Biosystematics  is simply known as “the study of biodiversity and its origins” and it is an art as much as science. In a broader sense, it is a science through which organisms are discovered, identified, named and classified with their diversity, phylogeny, spatial and geographical distributions. Definition of Systematics  The term Systematics is derived from Latinized Greek word systema , as applied to the systems of classifications developed by early naturalists.  Systematics is the science of diversity of organisms. BY.DATTA A NALLE 10

11. The scope of taxonomy and that of systematic in parti­cular are: 1. It works out a vivid picture of the existing organic diversity of our earth and is the only science that does so. 2. It provides much of the information, making it possible for the reconstruction of the phylogeny of life. 3. It reveals various interesting evo­lutionary phenomena, making them avai­lable for casual study by other branches of biology. 4. Almost entirely, it supplies information needed by the various branches of biology. 5. It provides names for each kind of organism, so that all concerned can know what they are talking about and such infor­mation can be recorded, stored and retrieved when needed. BY.DATTA A NALLE 11

12. 6. It differentiates the various kinds of organisms and points out their characteris­tics through descriptions, keys, illustrations etc. 7. It provides classification, which are of great heuristic and explanatory values in most branches of biology like evolutionary biochemistry, immunology, ecology, genetics, ethology , historical geology etc. 8. It is important in the study of eco­nomically or medically important organisms. 9. It makes important conceptual con­tributions in population thinking, thereby making it accessible to experimental bio­logists. It thus contributes significantly to the broadening of biology and to a better balance within biological science as a whole.    BY.DATTA A NALLE 12

13. Levels of Taxonomy α (alpha), β (beta) and Ƴ (gamma) taxonomy BY.DATTA A NALLE 13

14. Alpha (α) taxonomy: Alpha (α) taxonomy is the analytic phase in which the species are identified, characte­rised and named. At this level when a new species is discovered it is named in accor­dance with Linnaeus system of binomial nomenclature. Here priority is given to the one who publishes his work first. All prob­lems relating to species are dealt here. BY.DATTA A NALLE 14

15. Beta (β) taxonomy: Beta (β) taxonomy refers to the arrange­ment of the species into a natural system of hierarchial categories. This is done on the basis of easily observable, shared, structural features and evaluation of numerous charac­ters. Thus, β-taxonomy relates to the search of a natural system of classification. Each taxon would thus possess diagnostic fea­tures unique to that taxon . BY.DATTA A NALLE 15

16. Gamma (Ƴ) taxonomy: Finally, gamma (Ƴ) taxonomy designates the analysis of intraspecific variations and evolutionary studies. Much attention is paid to a causal interpretation of organic diversity — study of speciation. But in actual practice it is rather difficult to dissociate them because these overlap and integrate. There are only a few groups of animals (some vertebrates, especially the birds and a few insect orders like Lepidoptera etc.) where the taxonomy has reached up to the gamma level. Otherwise, in almost majority of the groups, the Works are still at the alpha and beta level. BY.DATTA A NALLE 16

17. Neo-taxonomy Or Experimental Taxonomy modern taxonomy which considers  species  to be the product of evolution, studies all its populations, varieties and sub- species  and gathers information from various fields before delimiting a  species  from its relatives. Julian Huxley (1940) developed the concept of New Systematics . It is related to the genetical studies based on a common gene pool for a taxon and become helpful to distinguish two dif­ferent taxa . Some modern procedures are applied to collect the data for morphology. The use of electron arid scanning electron microscope in different groups of inverte­brates such as protozoans , helminthes, ar­thropods to study the fine structures that become helpful in morphotaxonomy . BY.DATTA A NALLE 17