lession 0---Diversity in Living World: The Living World IMPORTANT CHARACTERISTICS OF LIVING BEINGS

Biology is the science of life forms and living processes. The living world comprises of an  amazing  diversity of living organisms. Life is unique, complex cellular organization of    molecules . According to Lamarck (1809) a body cannot have life if its constituent parts are   not cellular.various types of chemical reactions which lead to availability of energy, growth,     development, responsiveness, adaptation, are shown by the cells composing life.

   

The various traits shown by living being are as follows:

1. Cellular Structure: Each living organism is a complex entity formed of one or more cells.     The cells are made up of protoplasm , more popularly known as the living matter
.

2. Organization:  The living being has a definite shape and therefore an organization. Several components of the living organism cooperate and coordinate with one another for the well being of the whole organism.Each level of organization has its own properties which  are not found in its constituents.

 3. Energy: Energy is constantly required by the living organisms  to perform various activities and to overcome entropy or tendency to randomness. Food is the source of energy required  by every cell of the body.

   

4. Homeostasis ( Homoeostasis):  Every living organism has an internal environment  suitable for the functioning of the body organs. It is different from the external environment.  The external environmental change do not have much impact on the internal environment      since the living organisms have a self regulated system to adjust and maintain the internal     environment . The phenomenon is called as homeostasis ( Gk. homois- alike, stasis-     standing) Every cell in a multicellular organism possess homeostasis.. Therefore, a perfect  internal environment is maintained through self regulated system in multicellular organisms..

5. Growth: All living beings grow.  it is an irreversible increase in mass and cell number of an individual. A multicellular organism increases its mass by cell division. In plants growth  continues throughout life as they have meristematic areas where cell division occurs     regularly. In animals , growth occurs upto a certain age  after which cell division takes place  to replace the worn out and lost cells.Unicellular organisms also grow by cell division. Cell division is also a means of reproduction in them. In higher animals and plants, growth and reproduction are mutually exclusive. Living organisms show internal growth due to addition     of materials and formation of cells inside the body. Such a method is called intussusception.    (L-intus-within, suscipere-to receive)

  6. Reproduction:  Reproduction means to produce progeny possessing features more or less similar to those of the parents. The organisms can reproduce  asexually as well as sexually.There are different forms of asexual reproduction in different forms of organisms.  In unicellular organisms there is an increase in the number of cells, which indicates their reproduction.

7.Metabolism: All living beings show metabolism. It is defined as the sum total of all chemical reactions taking place in the body of an organism due to specific interactions amongst  different types of molecules within the interior of  cells . (Gk .metabole- change) . Metabolism     involves transformation of matter and energy within an organism and their exchange with the     environment. All activities of an organism including growth , movements, development responsiveness, reproduction etc. takes place due to the metabolism. The non- living   objects do not show metabolism. However, metabolic reactions can  be carried out outside the body of an organism using a cell free system .Such reactions are neither living nor non-  living. The isolated in vitro metabolic reactions can, however, be called biological reactions or     living reactions as they involve biochemicals. Metabolism are of two types namely: Catabolism   and Anabolism. Anabolism includes all the " building up" reactions e.g. synthesis of organic   compounds from CO₂ and H₂O during photosynthesis . Formation of starch from glucose ,     production of proteins from amino acids, formation of lipids from fatty acids and alcohols.     Energy is stored in the form of potential energy in the process. Catabolism  ( katabolism)     constitutes " breakdown reactions". It is also known as the destructive metabolism because it     involves breaking of complex substances into simpler ions.  Potential energy present in the  complex substances is converted into kinetic energy. Respiration is an example of  catabolism. It releases energy to perform various body activities.

8. Consciousness  All living beings respond to external stimuli. The external stimuli can be     physical, chemical or biological. The stimuli are perceived by sense organs in higher animals ,    e.g. eyes, ears, nose. Plants do not possess sense organs. However, they respond to     external stimuli  like light, water, temperature, pollutants, other organisms etc. Photo periods     influence reproduction in animals and plants which breed during a particular season.

9. Locomotion : Living beings show locomotion. i.e. they can move from one place to   another. However, plants do not exhibit locomotion.

10. Variation: Living beings also vary from one another. They have also shown evolution from  time to time.

11.Adaptations: (L: Ad- toward, apt- adjust) Useful inheritable variations or changes in form, function and behavior which helps an organism to  adjust well and successfully in its     environment are called adaptations.  It allows the organism to overcome seasonal and other     changes in the environment. Adaptations are of two types: namely  the short term  and the long term.

           

DIVERSITY IN THE LIVING WORLD:

Currently about 1.7 million species of animals and plants have been given scientific names,   1.2 million animals and 0.5 millions plants. Amongst animals , insects form the largest group  with 10.25,000 species. Existing living species are the outcome of about 3.5 billion years of     evolutionary process on this earth. nearly 15,000 new species are discovered every year.

Since it is nearly impossible to study all the living organisms, it is necessary to devise some     means to make this possible. this can be done by the classification of animals.

What is Taxonomy and Systematics ?

Taxonomy: It is the branch of Biology dealing with identification , nomenclature and     classification of living organisms. It deals with the rules and principles of classification. The term taxonomy was first coined by    A.P.deCandolle.      Carlous Linnaeus is considered the father of Taxonomy.

   

Systematics: It is the study of diversity of organisms including their comparative and  evolutionary relationship. The word Systematics was used by Carlous Linnaeus. It is based     on  comparative ecology, comparative Anatomy, Comparative Physiology, Comparative Biochemistry( G.Simpson;1967).

History of classification:

   

Plants and animals have been there on this earth before the human race evolved. Humans   named  animals and plants as for their basic needs. They were also classified in different     languages .

   

* Our Vedic literatures (2500 BC to 650BC) recorded about 740 plants and 250 animals.

* Chandyogya Upanishad classified animals into Divaja ( viviparous) Andaja (oviparous) and   Udbhija (minute animals).

* Post vedic literature such as Susruta Samhita (600 BC) classified all substances into   sthavara (immobile) eg; plants, and Jangama (mobile) eg; animals.

* Parasara grouped flowering plants (angiosperms) into Dvimatruka  (Dicotyledons) and  Ekmatruka ( Monocotyledons) . He characterized the former as jalikaparna (reticulate-veined     leaves) and the latter Maunlaparna (parallel - veined leaves).

* Greek Scholars Hippocrates (460-377 BC) who has  been referred o as the  Father of Medicine  and Aristotle (384-322 BC) referred to as the   Father of Biology", Father of Zoology, Father of     Philosophy   divided animals into four major groups like insects , birds, fish and whales.

* Aristotle and Plato 's pupil Theophrastus (370-285 BC) was referred to as the  Father of Botany in the book Historia     Planatarum    which classified plants on the basis of  their habit, form and texture into four     categories - trees, shrubs, under shrubs and herbs. 480plants have been described in that     book.

* Pliny the Elder (28-79 AD) introduced the first system of artificial classification. His book     Historia Naturalis has mention of 1,000 economic plants with about 2000 items.

* Charaka ( first century AD) was regarded as the Father of Ayurveda, listed about 340 plants and 200 animals in his book Charata Samhita on Indian medicine.

* In the late 17th century John Ray an English naturalist coined the term species for a group     of morphologically similar organisms and also tried to differentiate between genus and     species. The terms  monocotyledons and dicotyledons were also coined by him. He traveled     extensively all over Europe and described more than 18,600 plants and animals in his book     'Historia  Generalis Plantarum' . He also surveyed animal groups like insects, Quadrupeds,   and reptiles.

* Carlous Linnaeus  (1707-1778) a Swedish naturalist  referred to as Father of Taxonomy  published Systema Nature (1758) wherein he described 4326 species of animals. His   treatise , 'Species plantarum ' (1758) contained description of 5900 species of plants which     were classified on the basis of sexual characters . He also introduced Binomial     Nomenclature of plants and animals.

* In earlier systems of classification only external morphological observable characters which     could be studied with the naked eye were taken into account. The characters like root  modification, leaf venation, floral structures, number of cotyledons, etc were used in the     classification of flowering plants.From Aristotle to Linnaeus , everyone considered limited     characters, therefore this diverse groups of living organisms were placed into limited number  of groups. This phase of taxonomy led to the artificial system of classification. At the other end of the taxonomic spectrum other biologists assigned taxonomic affinity based on     evolutionary as well as genetic relationships among organisms besides morphology. They   ignored the morphological similarity or difference. This resulted in development of  phylogenetic classification or cladistics (Gk. Klados-branch, L. clados-branch).

* Cladistics classifies organisms according to the historical order in which the evolutionary     branch arose. This led to the emergence of new systematics or biosystematics.

New Systematics( Neosystematics. Biosystematics)

   

The concept of systematics considers  a species to be the product of evolution. This concept  was developed in 1940 by Sir Julian Huxley.

The important features of the systematics are:

* The species are not isolated. They are related amongst themselves. by common descent   and differ from them due to acquisition of different variations .

* The main stress is laid on the subspecies and population instead of species.. Therefore     the concept of population systematics has arisen.

* Statistical data are used to determine primitiveness or advancement of a species.

* Morphological definition of a species is replaced by biological definition. Besides morphology , biosystematics considers cytology, genetics,, ecology, biochemistry and physiology.This has led to the origin of many branches of systematics like Morphotaxonomy ( based on morphological traits) ,Cytotaxonomy ( based on cytological study), Karyotaxonomy ( based     on nucleus and chromosomes), Numerical taxonomy ( using statistical methods in  taxonomy) and Experimental taxonomy ( based on experimental determination of genetic interrelationships and effect of environment).

* A large number of specimens are studied to record variations before deciding the limits of the     species.

* The basic unit in new systematics is population.

* The new systematics is scientific and economical.

*     Numerical taxonomy is called phenetic or Adansonian taxonomy ( Adanson,1763 ). Turril (1938)  used the term Omega (  ω) taxonomy for biosystematics or neosystematics. His Alpha  ( α ) taxonomy ( Turril (1938) deals with collection and identification of organisms on the  basis of gross morphology , compilation of flora and monographs.

   

Basis of Classification:

   

Classification means the ordering of organisms into  groups. The branch of science that     deals with the study of principles and procedures of biological classification is called     taxonomy (A.P.de Candolle,1813).  Taxonomy enfolds the following fundamental elements.

* Identification: It idetermines the correct place in the system of classification and finds out the correct name of the organism.This is done with the help of keys. This is carried out by     determining its similarity with the already known organism. Suppose there are three plants a,  b, c. There is another plant d which is similar to the plant b. Then the recognition of plant d  as identical to the already known plant b is its identification.

*   Nomenclature ( L., nomen: name; calare; call) It is the science of providing distinct and     proper names to organisms as per the established universal practice and rules so that they  can be easily recognized and differentiated from the others.

* Classification: Classification is the arrangement of organisms into groups on the basis of their     affinities of relationships. It involves the placing of a kind of organisms or a group of different     kinds of organisms in particular categories depending upon the system of classification but in     conformity with the nomenclature system.

Nomenclature:

   

There is a need to standardize the naming of living organisms such that a particular  organism is known by the same name all over the world. This process is called  Nomenclature.

   

Nomenclature can be done in the following ways:

   

1. Vernacular Name: The name is given local language, it  varies from place to place , even   within the same country. The common names or the vernacular names are based on the peculiarity of the organism. They are brief, easier to to pronounce and easier to remember  by the residents of an area. The scientist cannot use the vernacular names because of the following reasons:

   

* Common names differ from region to region and language to language. It may have several  names in a given language.

* A common name may have different meaning in different areas.

*    Certain common names may be misleading as well as insignificant.  eg.  Silver fish  ( Lepisma is an arthropod),    Cuttle fish  (Sepia is a mollusca), Jellyfish (Aurelia,  is a     coelentrate) , Star fish ( Asterias is an echinoderm) create confusion in identifying the     organism. Similarly for plants several names are  misleading  as well as insignificant. e.g.  Kiss me quick for Euphorbia milli, Widows  tears  for Tradascantia and  Love in the mists  for  the plant Nigella damascena.

* A wrong common name cannot be easily corrected.

2. Scientific Name:  An universal name is given to the organism, or plant  on the  basis of  definite rules and criteria. The scientific name names ensured that only one name is given to     an organism and description of the organism should help the other people to arrive at the     same name in any part of the world. Each kind of organism , representing a species, is given     a different name to distinguish form the other. It should be ensured that that the same name     has not been used for any other organism before. The following have the practices of     providing scientific names to the organisms:

a) Polynomial nomenclature: Using many words for a name is called polynomial system of     nomenclature.   This system was used in the  medieval period i.e before 1750.  The       organisms   name consists of series of Latin Descriptive words. Such names have been     difficult to learn and remember. e.g. Caryophyllum: Caryophyllum saxatilis folis gramineus umbellatis corymbis.

b) Trinomial Nomenclature:  Using three words for a name is called trinomial system of     nomenclature. It was given by Lamarck, which consists of three words i.e. genus, species,  subspecies( in zoological literature) e.g. Corvus splendens splendens ( Indian Crow),     Brassica oleracea capitata ( cabbage).

    c) Binomial nomenclature: Using two words i.e. genus and species is called binomial system   of nomenclature. Swedish naturalist Carlous Linnaeus  established binomial nomenclature ,     although, it was first proposed by Casper Bauhin in his book PINAX.

Linnaeus gave some principles of the Binomial nomenclature in Philosophia Botanica (1751)      but the nomenclature was first used in Species Plantarum (1753) where names and     descriptions of 5900 species of plants were given. Later Systema Naturae  (1758) was     published by him wherein 4326 species of animals were described. Therefore Binomial     nomenclature is the system of scientific naming using genus as the first part and species  as      the second part .eg Magnifer indica (mango).Pisum sativum (garden pea) .

Rules for Binomial Nomenclature:

To provide uniformity , and to avoid confusion , 12th International Congress at Leningrad in     1975, laid down certain principles that were published in 1978 in the form of International     Code of Botanical Nomenclature (ICBN) and International Code of Zoological Nomenclature     (ICZN), The names of Bacteria and viruses are decided by International Code of     Bacteriological Nomenclature (ICBacN or ICBN)  and International Code for Viral     Nomenclature (ICVN)  respectively. Similarly , there is a separate International Code of     Nomenclature for Cultivated Plants (ICNCP). The important Rules are:

(i) A scientific name consists of two words in Latin or are latinised if derived from any other     language.

(ii) The first word is the genus and starts with a capital letter and second name is species     that stars with a small letter. The generic name is always unique for an organism and no two     living organisms can have the same generic name. the scientific name cannot have less than     three words and more than twelve words.

   

(iii) The specific name is written after the generic name which is like an adjective like its first     letter written in small form. A botanical specific name may begin with capital letter if  it     denotes a person or a place e.g. Pentoxylon Shanil, Tolypella Jwelli etc. A species can be     named only if it is assigned to a genus. The same specific name can be assigned to two     genera but two species of the same genus cannot have the same specific name. e.g     Magnifera indica (mango), Holotalea indica (chilbil)

(iv)The genus and species names are in italics when typed but underlined when written with     hand.

(v) The authors name is also written in the abbreviated form after the species name and it is     printed in Roman , while handwritten is never underlined.

(vi) The generic epithet , specific epithet and the authors  citation collectively form the     Binomial epithet .eg; Magnifera Indica Linn.

(vii) A hyphen is used when there are two or more words in species name forming compound     specific name. e.g. Hibiscus rosa -sinensis.

(viii) The names of subfamilies and families should be based on the name of the type genus     e.g. family Graminae is changed to Poaceae,  Compositae changed to Ateraceae. etc.

(ix) Linnaueus introduced the first naming system in 1758 in his  10th edition of Systema Naturae. In case two or more names are given , the older one is considered as the valid name and the subsequent  ones are the synonyms.

(x) Rule of Priority: The most important as per the rules of ICBN.

(xi) When the generic name and specific name are the same it is known as TAUTONYMS     e.g. Rattus rattus. It is not recognized by Botanists. When the species name and the subspecies names are the same then it is known as AUTONYMS e.g Corvus splendens splendens.   When two different plants have the same name then they are called HOMONYMS. eg. Prunus dulsi ( almond and plum).

   

Taxonomic Hierarchy:

(i) The main aim of the taxonomic study is to assign organism an appropriate place in     a     systematic framework of classification. This framework is called as taxonomic hierarchy by     which the taxonomic groups are arranged in a definite order , from higher to lower     categories, depending upon their relative dimensions. The hierarchy indicates the various     levels of kinship. Nearer the categories in hierarchy the greater is the similarity between the organisms.

(ii)    It is also known as the Linnaean hierarchy because it was first proposed by Linnaeus. He introduced five categories initially i.e Class, Order, Genus, Species, Variety. The last one was discarded and three added so that now there are seven obligate categories i.e. Kingdom, Division,or Phylum, Class, Order, Family , Genus and Species.. The Botanists use Division in place pf Phylum. as a category in the classification of plant kingdom. In order to make t axonomic position of species precise , certain subcategories and super categories have been added to this list and they are known as intermediate categories. e.g. sub kingdom, super phylum, or super division, subdivision, superclass, subclass, super order, sub order,, sub family, tribe, sub species, variety etc.

(iii) Both animals and plant kingdoms, the lowest category is the species and the highest is the Kingdom. The placement of groups of individuals or organisms in species ,      genus and     up to phyla  or Division is determined by the  similarities in their  characters and the relationships. The categories in the hierarchy are in the ascending     order. As we go from species towards Kingdom the number of similar character  decreases.

(iv) Of the various categories   of classification, only the species have a real existence in nature, others are nearly man made convenient and arbitrary groups without actual existence in nature. Species is the basic unit of classification.

Taxon  ( Gk. Taxis: arrangement):

(i) The word Taxon signifies a taxonomic group of any rank which represents the real     biological organisms included in a category like maize (species), roses (genus), grasses ( family), conifers (order) dicots (class), seed plants (division) etc.

(ii) The term was introduced by Adolf Meyer (1926) for animal groups. H.S Lam first proposed the term 'Taxon' for plants.

(iii) There is a confusion over the use of Taxon and Category. Bryophyta is a Taxon while Division is a category. Similarly Zea mays is a Taxon and species is a category.     Summarizing, Category is an abstract and Taxon represents the real organism.

       

Obligate Categories:

   

The Obligate categories used in the classification are explained as follows:

Species:

* Species occupy a key position in the classification.

       

*species is the basic unit for understanding taxonomy and evolution. It is a  natural     population of individuals or group of populations which resemble one another in all essential morphological and reproductive characters, carry same type of genetic     material so as to     breed freely amongst themselves under natural conditions in order to provide fertile off springs.

* The species is also called genetically distinct and reproductively isolated natural population e.g. mango(Magnifera indica) , Potato ( Solanum tuberosum), tulsi (Ocimum sanctum) and lion ( Panthera leo) etc. In this case, indica , tuberosum, sanctum, and     leo are species of genera Magnifera, Solanum, Ocimum and Panthera respectively.

* A species may have subgroups, called subspecies or varieties, showing certain distinct features of their own.

Concept of species:

(i) Static concept of species was given by Linnaeus, species is fixed and immutable.

(ii) Dynamic concept of species was given by Lamarck, species is mutable and  dynamic.

(iii) Typological concept of species: most widely held and most simple species concept.     according to this concept there is   an  ideal pattern for each species. Individuals of     the     species match each other in all respect. Variation, if any, is due to imperfection of physical world. Such a concept is typological because it conceives an ideal     type of body for each species.

(iv) Nominalistic concept of species: species have no existence , only the individuals do so.

(v) Biological Concept of species ( was given by Ernst Mayr): Species is the fundamental     unit of classification . A species  is a group of organisms (a) which are closely related ( structurally and functionally); sharing a common gene pool,(b) which  can interbreed freely     and produce fertile offsprings in a natural environment.

Exception:

   

(i) Male Donkey + Female Horse:  The progeny is a Mule

(ii) Female Donkey + Male Horse : The progeny is a Hinny

Cross is natural but progenies are sterile

(i) Male Tiger+ Female Lion: The progeny is Tigon

(ii) female Tiger + Male Lion: The progeny is Liger

Cross is in captivity but progenies are fertile

   

   

Types of Species:

(i)  Morphospecies: Species erected on the basis of morphological characters    only.

(ii) Taxonomic species: Species having a definite Binomial name.

(iii) Sibling species: True species which do not interbreed but are otherwise   difficult to separate on the basis of morphological characters alone. Drosophila    pseudoobscura and Drosophila persimilis.

(iv) Allopatric species: Species having exclusive areas of geographic distribution.

(v) Sympatric species: Species having overlapping areas of geographic   distribution.

(vi) Parapatric species: Species with adjacent geographic ranges meeting in   very     narrow zone of overlap.

(vii) Allochronic species: Species belonging to different time period.

(viii) Neontological species: Living species.

(ix) Synchronic species: species belonging to same period of time.

(x) Polytypic species: Species with two or more subspecies.

   

Genus:

* It is a higher category above the level of species. It is a group of species which are  related and have less characters in common as compared to species.  Potato (Solanum tuberosum) and Brinjal (Solanum melongena )belong to different species but     belong to the same genus Solanum.  Similarly  lion (Panthera leo), leopard (Panthera     pardus), tiger (Panthera tigris) and jaguar (Panthera onca) have several common features  and are included in the same genus Panthera.

* A genus may have a single species ( monotypic) e.g. Homo sapiens or it may have several     species (polytypic) e.g. Panthera , Solanum etc.

   

* All the species of a number of common features called correlated characters . the close resemblance indicates a common ancestory for all the species of a genus.

* There is no rule fo suffix in genus and species.

   

Family:

* Family is represented by a group of related genera that are more similar to each other than with the genera of other families.

       

* All the genera of a family resemble one another in certain co-related characters indicating     a common ancestory.

* The genera like Solanum, Petunia, Datura, Atropa etc. based on similarities are placed in the Family Solanaceae.

* In case of  animals; lion, leopard, tiger, jaguar, from genus Panthera and cat from genus Felis  are included in the family Felidae.

* In Plants the family ends with the suffix -aceae and subfamily with -oidae while in animals the suffixes are -ideae for family -inae for subfamily,-ini for tribe ( between subfamily and genus).

Order:

* It is an assembly of families resembling one another in a few characters. These     characters are less similar as compared to many genera put in a family.Families like      Solanaceae. and Convolvulaceae are put  in the Order Polimoniales on the basis of some      related floral characters. Likewise Order carnivora contains related families of Canidae,     Felidae, Ursidae( bear) and Hyaenidae (Hyaena).

   

Class:

 *   It is a taxonomic category made up of one or more related orders. e.g. mammalia has a   number of orders like Carnivora, Rodentia , Insectivora etc.

* It ends in suffixes  -phyceae, -opsida, and -ae in plants. The suffix is not fixed in case of  animal.

       

Phylum or Division:

   

* Phylum or Division consists of one to several related classes having similar character.

* In animals, the phylum Chordata includes classes pisces, Amphibia, Reptilia, Aves, and mammals. since all classes at some stage of of their lives have had a common character like     the presence of a notochord, dorsal hollow nervous system, and pharynx perforated by gill slits.

* The division is given he suffix -phyta and the subdivision -phytina.

       

Kingdom:

       

*        In general it includes all the organisms which share a set of  distinguishing common  characters.

*      It is the highest category of biological classification .Plants are put in the plant kingdom and the animals put in the animal                kingdom.. R.H.Whittaker (1969) has recognized five kingdoms of organisms-Monera , Protista, Fungi, Plantae (Metaphyta)             and animalia (Metazoa).

Taxonomical Aids:

   

Laboratory and field studies are equally important for the identification of various species.     The information gathered has to be stored for future studies.  The actual specimens are collected , preserved, and stored for verifications if required later on. This helps in the identification of the species and there after they can be easily placed in the taxonomic  hierarchy. There are various aids like herbaria, botanical gardens, museums and zoological     parks .

       

Herbarium:

   

A herbarium is defined as a collection of plants that is dried , pressed and preserved on the sheets. The sheets are arranged in accordance with the accepted system of classification (Betham and Hooker system). The storage of sheets form a repository for future use. It     provides a quick reference system and useful in the taxonomical studies. All the institutes concerned with Botanical studies maintain herbaria.

History of Herbaria:

Majority of the world  famous herbaria originated from the botanical gardens.The first herbaria was set up at Pisa in Italy by a professor of botany Luca Ghini.  His students bound the paper sheets having plant specimens mounted in them into book volumes , and spread the art of herbarium throughout Europe.

Herbarium Technique:

   

(i) To collect specimens, simple tools like digger has to be carried to dig roots. scissors for cutting twigs , pole and a hook for collecting parts of tall trees.

(ii) Vasculum and polythene bags are used to temporarily store fresh shoots to avoid loss of     moisture and distortions by drying and shriveling up. Vasculum is a box 45-60 cm length,  20 cm width and 25 cm depth.

(iii) Succulent parts, fruits, tubers, rhizomes, are preserved in bottles having FAA ( formalin +    acetic acid, alcohol). Some of them can also be dried and kept in a packet.

(iv) Both Vegetative and Reproductive parts are to be collected in in the case of herbs.  The     twigs  with leaves, inflorescence and flowers are collected from the shrubs and trees.

(v) Generally sufficient number (5-6) of a particular type of specimen is to be collected. The process of collecting more is necessary because during the process of collection , transport     and presyration  some specimen might get damaged. The specimens are referred to as  'assigned collection number', which are called the field numbers.

(vi) The specimens are spread out in a short time. They are dried by keeping them within the  folds of old newspapers. It is necessary to change these newspapers at regular intervals to   avoid fungal growth. Complete specimens with all parts are dried in a plant press. The   plant   press consists of a set of two boards  with straps , which help in tightening the newspaper sheets with specimens between the boards.

(vii) The bigger specimens are not cut but they are folded. Some leaves are spread for  showing dorsal surface and others to show ventral surface.

(viii)The dried specimens are pasted on the herbarium sheets of standard size (41x 29 cms).   Specimens before fixing are kept upside down on paper sheet, glue, or adhesive is applied   and then they are mounted on the herbarium sheet.

(ix) All the pasted specimens are sprayed with 0.11% mercuric chloride which is a   fungicide,     pesticides like DDT, Napthalene and carbon disulphide, to check the growth of fungi.

(x) The heavy parts of plants like seeds , fruits are put in a packet and attached to the  sheets.

(xi) Label (7x12cms) is pasted over the right hand corner and caries the following     information:

   

Collection Number

1  Place/ Locality

2 Name of the collector

3 Date and Time

4 Common English name

5 Vernacular name

6  Scientific Name

7  Family

8 Institution

The information about the specimens is complied and published in a form of a book   (Flora) which gives the list of total species in a particular region , country or continent together with a brief  description of each.

The herbaria are classified as:

(i) Major or National Herbaria:  They cover the flora all over the world and serve the   purpose of research a well as identification.

(ii) Minor Herbaria: It includes smaller herbaria which serves the purpose of a small area like a district .

(iii) College/ University Herbaria: Primarily for teaching and post graduate research.

   

A list of Major Herbaria of the world with standard abbreviations and approximate   number of specimens:

1. Royal Botanical Gardens, Kew , England (K)      ( 6.5 million specimens)

2. Museum of Natural History, Paris , France (6 million specimens)

3.    Central National Herbarium in  Indian Botanical gardens , Kolkata, India (CAL) ( 2 million specimens)

4. Royal Botanical Gardens , Edinburgh (E)    (1.5 million specimens)

5.Herbarium of the forest Research Institue, Dehradun (DD)      (3 billion    specimens)

6. Herbarium of the National Botanical Research Institute, Lucknow (LWG) (80,000         specimens)      

The complete listing and description of the plants growing ina particular area are  published in flora or manual like:

1. Flora of British India by J.D Hooker.

2. Flora of Delhi by J.K Maheswari.

3. Flora Indica by William Roxburgh

4. Flora Simlensis by H. Collet

5.Flora of Bombay by T.Cook

6.Flora of Bihar and Orissa by H.H. hans

7.Flora of Bengal by D. Prain

8. Flora of Mussorie by M.B. raizada and H.O. Saxena

Functions of a Herbarium:

       

1.The two primary functions of herbarium are accurate identification and alpha taxonomic  research.

2.The secondary function included closer interaction between the student of general  systematics and the herbarium.

   

The most important functions of a national herbarium are enlisted below;

a)To preserve the plant wealth including type material and palaeobotanical collections.

b) To carry out exchange and loan of preserved plant material for research , exhibitions      etc.

c) To carry out research pro grammes of fundamental and applied value

 

d)Compilation of Flora, manuals and Monographs

e) Preservation of voucher specimens.

f) Knowing ecology of different places.

g) To fulfill public needs by supplying materials and scientific information about  by arranging training courses , exhibitions etc.

   

Botanical Gardens:

   

Botanical gardens are collections of living plants maintained for reference . However from the time of Theophrastus (about 380 to 287 B.C)  gardens have contributed to the science of Botany. In ancient Indian culture , cultivation of food and medicinal plants is known since 4000 to 2000 B.C. The Hanging gardens of Babylon are amongst the wonders of the ancient  world.     A botanical garden extensively growing trees and shrubs is called arboretum.

During the middle ages , from A.D 600-1600 there was a lapse in learning and introduction of plants. In the seventeenth century there was revival in the interest and by eighteenth century     most of the famous botanical gardens known today had already been established. There are about 525 botanical gardens in various countries but only 125 with documented collections  of authenticated taxa.

The functions of a Botanical garden are:

(i)  Provide records of local flora for monographic work.

(ii) Provide facilities for collections of living plant material.

(iii) Supply seeds and material for botanical investigation.

(iv) Botanical gardens have an aesthetic appeal and attract a large number of visitors    for observation of general plant diversity.

   

           

The International Association of Botanical Gardens was established in 1962. This  association has published the International Directory of Botanical Gardens (1983).

   

Some of important Botanical Gardens are listed below:

(i) Royal Botanical Garden, Kew, England: It was founded in 1759 by William Alton but was     officially opened in1841 and was called the 'Botanical Capital ' of the  World . Sir J.D Hooker was one of its Directors. It is famous for its Alpine house , Rose     Garden/ Arold house , Green house, temperature house, Bamboo garden and Lily pond. It is     associated with Jodrell laboratory of experimental taxonomy. It is spread in 200 acres and   Kew satellite is spread in 400 acres. It is famous for Acacias, Acer, Rhus, Citrus, Rosa,     Prunus, Magnolia. It has Chelsea Physic Garden for floriculturists.  Kew Bulletin and index kewensis are the two premiere publication of the Kew Garden.

(ii)    Orto Botanico (Padua Gardens), Italy:  It is said to be the first botanical garden. It is famous for grasses, alliums,irids, Paeonias, succulents and hydrophytes.

(iii) Pisa, italy: Almost as lod as Padua Gardens, it was the first to introduce  palaentological  practices for the study of plant fossils.Caesalpino and John Ray have been associated with     this garden.

(iv) Villa Taranto ,(Italy) It is the most beautiful garden in Italy from horticulture point of  view.

(v) Royal Botanical garden, Edinburgh, Scotland: Founded in 1760. It is the second   oldest garden in Great Britain. This garden is famous for Rhododendrons, azaleas and Himalayan     alpine plants. which is a demonstration garden and a glasshouse. It has the finest rock garden in the world.

(vi) Botanischer Garten, Berlin: Established in1646. A.W. Eichler and Adolf Engler are two of  its famous directors.

(viiii) Botanical Garden, Uppasala: Founded by O.J. Rudbeck in 1655, Linnaeus  succeeded him as director in 1742.

(ix) Main Botanical Garden ,Moscow: It is the largest botanical garden spread over an area  of 900 acres.

   

Botanical Gardens of India:

   

(i) Llyod Botanical Garden- Darjeeling

(ii) National Botanical Garden- Lucknow

(iii) Tamil Nadu Government Garden- Ootacamund

(iv) Lalbagh gardens- Bangalore

(v) Saharanpur Botanical Gardens- Saharanpur

   

Special kinds of gardens:

a) Arboretum- main collections are of woody species

b) Pinetum- Mainly collections of conifers

c) Orchidarium- A garden containing of Orchids e.g. National Orchidaria in BSI , Shillong and     Coimbatore.

d) Bambusetum- With main collection of Bamboos.

Museums

•    These have collections of preserved plants and animals for study and reference . These are prepared tp preserve algae, fungi, mosses, ferns, parts of gymnosperms, fruits, underground storage organs etc. Animals are usually preserved in formaldehyde solutions , stuffed or in skeletal forms.

•    The collected specimens are correctly identified and labelled. The specimens are stored and a catalogue is prepared for future reference.

•    The objective of preparing a museum is to record information and preserve specimens for taxonomic studies.

•    The animals are not killed unneecessarily . The students of Botany and Zoology are asked to collect and preserve plants, plant parts, dead animals.

   

•    The importance of plants in every day life can hardly be over estimated as most of the things that we need have got their origin in some plant part or the other. The Botanical specimens are mainly arranged in two galleries (i.e. Systematic Botany and Economic Botany). In the Systematic Botany Gallery, the exhibits are arranged in their evolutionary order starting with primitive Cryptogams i.e. algae and fungi. Families of flowering plants are arranged according to the Bentham and Hooker system of classification. In the Morphology Section, the models of different types of inflorescence, ovules, pollen grains and embryosacs are displayed with descriptive labels. Specimens of Systematic Botany  include preserved herbariums wet specimens and photographs.

Keys:

     

(1)   A Scheme for identification of plants and animals is known as Key. It refers to  alternate characters  arranged in such a manner that helps in the identification of an organism by selecting or eliminating the characters according to their presence or absence in the organisms.

(2) The taxonomic keys are based on the contrasting characters in couplets. It represents     the choice between two  opposite options. Only one is accepted and the other is rejected. Each statement in the key is called a lead.

(3)Separate taxonomic keys are required for each taxonomic category like family, genus, or species. These are more useful in identifying the unknown organisms.

(4)The keys are of two types: the indented type or the yoked type and the bracketed type.

(5)The correct choice has to be made. In the Bracketed Key the pairs of contrasting  characters are used for identification and they are given numbers in brackets. The  numbers on the right indicate the next choice of paired contrasting characters.

INDENTED KEY

Character    `                                                                                                Genus

Carpel single ovuled; fruit achene                                                                    Clematis

Leaves opposite,compound                                                                             Clematis

Petals absent,leaves without tendril                                                                 Clematis

Petals present, third or terminal leaflets modified into tendril Narvelia       Narvelia

Leaves alternate or radical                                                                              Anemone

Carpel many ovuled; friut follicle                                                                      Nigella

Carpel united at base; flowers regular                                                              Nigella

Carpels free at base; flowers irregular                                                              Aconitum

BRACKETED KEY

Character                                                                                                     Genus

(1) Carpel single ovuled; fruit achene                                                                     2

(1) Carpel many ovuled fruit follicle                                                                        4

(2) Leaves opposite, compound                                                                             3

(2) Leaves alternate, radical                                                                           Anemone

(3) Petals absent , leaves without tendril                                                       Clematis

(3) Petals present, third or terminal leaflets modified into tendril.              Narvellia

(4) Carpels united at the base; flowers regular

    Nigella

(4) Carpels free, flowers irregular                                                                 Aconitum

Other Taxonomic Aids:

1)    Some other taxonomical aids are monographs, manuals, publications etc.

2)    Monographs give comprehensive account of complete compilation of available information of any one family or genus at a given time.

3)    Manual contains compiled information about the covered area, keys, description of families, genera and species.

4)    Publications like peroidicals and Dictionaries provide information about addition and updated information.

5)    Flora contains the actual account of habitat and distribution of plants of a given area.

6)    The Botanical srvey of India is an organization for exploring the plant wealth of the counry. The headquarters are in Kolkata, and the zonal offices are at Dehradun(North) , Pune (west), Coimbatore (South),  Shillong (East), Allahabad (Central).

7)    The Indian Botanical Gardens have the great banyan tree ( Ficus bengalensis) which is about 200 years old.