BIOLOGY

                                       BIOLOGY

                  DIVERSITY IN LIVING ORGANISM

Biology is the science of life forms and living processes . The living world comprises an amazing diversity of living organisms. Early man could easily perceive the difference between inanimate matter and living organisms . Early man deified some of the inanimate matter and some among the animals and plants . A common feature of all such forms inanimate and animates objects was sense of awe or fear that they evoked . The description of living organisms including humans beings began much later in human history . Societies which including in anthropocentric view of biology could register limited progress biological knowledge . systematic and monumental description of life forms brought in , out of necessity , detailed systems of identification , nomenclature and classification .

NOMENCLATURE

             

General Rules for Nomenclature :

1. Biological names are generally in Latin and written in italics. They are Latinised or derived from Latin irrespective of their origin. 
2. The first word in a biological name represents the genus while the second component denotes the specific epithet. 
3. Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.
4. The first word denoting the genus starts with a capital letter while the specific epithet starts with a small letter. 

 

Nomenclature of Living Beings

Biodiversity :- The planet earth is full of variety of animals and plants. Every distinct geographical location has its own set of flora and fauna. This variety of living beings found in a given geographical area is called biodiversity of that area.

Nomenclature and Identification :- Because of the huge diversity present in the living world it became necessary to develop a system to classify and name all plants and animals. International Code for Botanical Nomenclature has developed a system for identification and classification of plants. International Code of Zoological Nomenclature has developed a system for identifying and classifying the animals.

 

 

TAXONOMY

                  Taxonomic Categories 

Classification involves hierarchy of steps in which each step represents a rank or category. Since the category is a part of overall taxonomic arrangement, it is called the taxonomic category. All categories together constitute the taxonomic hierarchy. Each category represents a rank and is commonly termed as taxon .

Species :-

A group of individual organisms with fundamental similarities is called species. Certain distinct morphological characters distinguish one species from the other closely related species. For example; Solanum tuberosum (potato), Solanum nigrum (Black nightshade) and Solanum melongena (aubergine or eggplant) are different species from the genus Solanum. Similarly; Panthera leo (lion) and Panthera tigris (tiger) are different species from the genus Panthera.

Genus :-

A genus is a group which is comprised of closely related speciesWe can say that genera are aggregates of closely related species. For example, potato, tomato and brinjal are three different species but all belong to the genus Solanum. Similarly; Lion (Panthera leo), leopard (P. pardus) and tiger (P. tigris) belong to the genus Panthera.

Family :

The next category, Family, has a group of related genera with still less number of similarities as compared to genus and species. Families are characterised on the basis of both vegetative and reproductive features of plant species. For example; three different genera Solanum, Petunia and Datura are placed in the family Solanaceae. Similarly; genus Panthera, comprising lion, tiger, leopard is put along with genus, Felis (cats) belong to the family Felidae.

Order :

Order is the group of families which exhibit a few similar characters. The similar characters are less in number as compared to different genera included in a family. Plant families like Convolvulaceae, Solanaceae are included in the order Polymoniales on the basis of floral characters. The animal order, Carnivora, includes families like Felidae and Cancidae.

Class :

The group of related orders is called class.  For example; order Primata comprising monkey, gorilla and gibbon is placed in class Mammalia along with order Carnivora that includes animals like tiger, cat and dog. Presence of mammary glands is one of the common characters in these orders.

Phylum :

In the Animal Kingdom; group of closely related classes is called phylum. In the Plant Kingdom; group of closely related classes is called Division. For example; fishes, amphibians, reptiles, birds along with mammals belong to Phylum Chordata. The common features for Chordata are; presence of notochord and dorsal hollow neural system.

Kingdom :

The group of all related phyla is called Kingdom. For example; all heterotrophs; which do not have cell wall and are eukaryotic are kept under the Animal Kingdom. All autotrophs which are eukaryotic are kept under Plant Kingdom.