DIVERSITY IN THE LIVING WORLD

#SHORT NOTES NEET PREPARATION (Chapter 1) – DIVERSITY IN THE LIVING WORLD

Variety of living organisms – plants, insects, birds, pet, animals, microorganisms

Number of species – 1.7 to 1.8 million – called biodiversity or the number and types of organisms present on earth

Nomenclature – method to standardize the naming of living organisms (particular organism) is known by the same name all over the world

Identification – nomenclature or naming is only possible when the organism is described correctly

ICGN AND ICZN (International Code for Botanical Nomenclature and International Code of Zoological Nomenclature) – Scientific Names are given. Each organism has only one name. Name shouldn’t be used for any other known organisms

Biologists follow universally accepted principles to provide scientific name to known organism

Each name has two components – the generic name and the specific epithet. The system of providing a name with two components = called Binomial nomenclature.

Naming System is given by Carolus Linnaeus

Naming system has two word format – example Mangifera indica (Binomial name) – Mangifera = Genus and indica = species (specific epithet)

Universal Rules of 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 (RULES WITH EXAMPLES)

1. Name in Latin language and italics (Mangifera)
2. First word (Mangifera = Genus) Second word (indica = specific epithet)
3. Both words when handwritten – is separately underlined or printed in italics Mangifera indica
4. First word Genus – Capital Letter (Mangifera) and Second Word Specific Epithet – Small Letter (indica)

After specific epithet (at the end of biological name = author name appears (abbreviated) – example Mangifera indica Linn (Species was first described by Linnaeus)

CLASSIFICATION

Purpose of Classification – a method to study all the living organisms

Classification = process which organisms is grouped into convenient categories based on observable characters

Example: we easily recognize groups such as plants or animals or dogs, cats or insects

Taxa = a scientific terms for these categories

Taxa can indicate categories at very different levels

Example: “animals”, “mammals”, and “dogs” represent taxa at different levels

Based on characteristics, all living organisms can be classified into different taxa = this process of classification is called Taxonomy

For Taxonomy = external and internal structure, structure of cell, development process and ecological information of organisms are essential and form the basis for study

Basic Taxonomy = characterization, identification, classification and nomenclature are the processes

SYSTEMATICS = Knowing more about different kinds of organisms and their diversities, but also relationships

Word “systematics” = derived from the Latin word “systema” which means systematic arrangement of organisms

Linnaeus used systema Naturae as the title of his publication

Scope of systematics includes identification, nomenclature and classification.

Systematics takes into account evolutionary relationships between organisms