chapter 3 | Biodiversity part1


Definition:

The term “biodiversity” has been derived from ‘bio’ and ‘diversity’. “Diversity” means variety within
a species and among species. 
Biodiversity is a measure of the variety of organisms present in different ecosystems.

The diversity of plants’ (flora) and animals’ (fauna) in a region depends on climate, altitude, soils
and the presence of other species. Biodiversity is not distributed evenly on Earth.

Importance of biodiversity


  • Biodiversity provides food for humans. 
  • Drugs are derived, directly or indirectly, from biological sources.  
  • Industrial materials e.g. building materials, fibres, dyes, resins, gums, adhesives, rubber and oil are derived directly from plants.
  • Biodiversity plays important role in making and maintaining ecosystems. 
  • It plays a part in regulating the chemistry of our atmosphere and water supply.
  • Biodiversity is directly involved in recycling nutrients and providing fertile soils.
Classification - Aims And Principles

biologists classify the organisms into groups and subgroups to study a large collection of organism Biological classification is a method by which biologists divide organisms into groups and subgroups.

Aims of Classification

The branch of biology which deals with classification is called taxonomy and the branch which deals
with classification and also traces the evolutionary history of organisms is known as systematics.

The main aims of both these branches are;
• To determine similarities and differences among organisms so that they can be studied easily.
• To find the evolutionary relationships among organisms.


Taxonomic Hierarchy

The groups into which organisms are classified are known as taxonomic categories or taxa (singular “taxon”). The taxa form a ladder, called taxonomic hierarchy. All organisms are divided into five kingdoms. So kingdom is the largest taxon. On the basis of similarities, each kingdom is further divided into smaller taxa in the following way:

• Phylum (Division: for plants and fungi): A phylum is a group of related classes.
• Class: A class is a group of related orders.
• Order: An order is a group of related families.
• Family: A family is a group of related genera.
• Genus: A genus is a group of related species.
• Species: A species consists of similar organisms.





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