Botany

Biology can be studied under the following headings: -

Ecosystem Diversity
Species Diversity
Genetic Diversity

Ecosystem Diversity
The variation existing among the Ecosystems due to change in structural and functional aspect of biotic community.

Ecosystem

Ecosystem is a dynamic relationship amongst the plants, animals, micro-organisms, gene contained and their environment where flow of energy and cycling of Nutrients takes place.

Species Diversity
Group of Individuals which can inter-breed in their Natural Environment to produce fertile off springs is called species. The variety of species found in a particular area is called Species Diversity. The total number of species found in any region is called species richness.

According to Wilson (1980) there are 5-30 million of Species of living being that exists.

Genetic Diversity
It is another form of Diversification of Living Beings all around the world in which there is differentiation or variation between the same species and from the same family. The most abundant example of this is the two sons or daughter of same family having same Genetic material but different Genetic Character.

Taxonomy
The branch of Biology Dealing with the Identification, Nomenclature and Classification of Living Organism is called Taxonomy. Taxonomy is derived from two Greek Word Taxis and nomous which means arrangement and law of rules respectively. The word collectively means the lawful arrangement of Living Organisms.

[Note: - French Botanist De Candole(1813) coined the term Botany for the First time.]

History of Taxonomy

Some Great Taxonomist

1. Aristotle (384-322 B.C)

Aristotle is known as the father of Biology who is a Greek Philosopher. He classified few hundred plants and animals as well. He classified Plants on the basis of Habit/ Nature dividing them into Herbs, Shrubs and Trees. In case of Animal, he divided animals on the basis of Habitat dividing them into Land, Air and Water.

2. Theophrastus (370-285 B.C)

Theophrastus is also known as Father of Botany. Based on the forms and Textures, Theophrastus divided plants into four groups which were Herbs, Shrubs, Under Shrubs and Trees. Also he divided plants on the basis of life spans which were Annual, Biennial and Perennial. He also distinguished between Phanerogams and Cryptogams. He classified 480 species in his book Historia Plantarum.

3. Jhon Ray (1628-1705 B.C)

Jhon Ray was an English Taxonomist. He classified all the plants into two groups which were Herbs and Trees. He developed key system for the classification of Plants and Animals. He was the first person who recognized the difference between Genus and Species.

Species was termed by Jhon Ray. He also described 18,000 plants in his book Historia Plantarum (3-volume.)



Carolous Linnaneus (1907-1978)

He was a Swedish Taxonomist and he is regarded as the father of Taxonomy. He is the pioneer person in the field of Biology. He made an attempt to classify whole thing living organism into two kingdoms.

He described 5900 species of plants under 1000 Genera “Species Plantarum” in 1753. He also described 4200 animals in his book Systema Naturae (1758).

He developed the Binomial System of Nomenclature in which every organism are given Scientific Name in tow words which were Generic and Species. He also proposed the Hierarchical System of Nomenclature.

Classification: –

It is the system of arrangement of living organism into different group on the basis of the similarities and differences in their characters and further placing them into Hierarchy of categories like Kingdom, Division/phylum, Class, Order, Family, Genus and Species,

Basically, Classification is of three types: -

Artificial Classification System.
Natural System of Classification.



1. Artificial Classification System

In this system, Organisms are classified by considering only one or very easily observed characters like (Height/ form/ Texture). This system is frequently applied on the field due to its simplicity and convenience.

[For Example: - Classification System proposed by Aristotle, Theophrastus and Jhon Ray are the main example of this Classification System.]

Linnaeus classified plants on the basis of number of Stamens present in the Flower. He kept all the plants with single stamen into separate class monandria.., two stamen into class diandria and,,,,,,so on… with 24th group which includes Cryptogamia.

Limitations of Artificial Classification: –

It is based on only one or very few characters so it can’t explain actual position of organism.
It can’t give any natural relationship among the different groups.
Un- related animals may come together in a group. Example: - Butterfly, Birds and Bats
Closely related animals may be separated into different group. Example: – Rat, Bat and Whale