Biology - Diversity in Living Organisms

Introduction

• Biodiversity term is used to define the diversity of life forms.

• Biodiversity is a word more often used to refer to the variety of life forms found in a particular geographic region.

• Diversity of life forms of a geographic region provides stability in the respective region.

Base of Classification

• Greek thinker Aristotle first classified animals based on their place of residence whether they lived on land, in water, or in the air.

• Later, all the living organisms are identified and categorized on the basis of their body design in form and function.

• The idea of evolution was first described by Charles Darwin in 1859 in his book namely – The Origin of Species.’

• Charles Darwin first described this idea of evolution in 1859 in his book, ‘The Origin of Species.’

Hierarchy of Classification Groups

• Some biologists, namely Ernst Haeckel (1894), Robert Whittaker (1959), and Carl Woese (1977) have attempted to classify all living organisms into broad categories and named them ‘Kingdoms.’

• Whittaker categorized into five kingdoms namely −

  • Monera

  • Protista

  • Fungi

  • Plantae

  • Animalia

• Further, these kingdoms have been classification by naming the sub-groups at various levels as −

• Let’s discuss each kingdom in brief −

Monera

• The organisms of Monera kingdom do not have a defined nucleus or organelles, neither do any of them show multi-cellular body designs.

• The examples of this monera kingdom are bacteria, anabaena, blue-green algae or cyanobacteria, and mycoplasma.

Protista

• The organisms of Protista kingdom include many kinds of unicellular eukaryotic organisms.

• The examples of Protista kingdom are algae, euglena, diatoms, and protozoans, etc.

Fungi

• The organisms of fungi kingdom are heterotrophic eukaryotic organisms.

• The organisms of this kingdom use decaying organic material as their food and therefore, they are also known as saprophytes.

Plantae

• The organisms of this kingdom are multicellular eukaryotes with cell walls.

• The organisms of plantae are autotrophs and they use chlorophyll for making their food (i.e. photosynthesis).

• All plants are examples of plantae kingdom.

Animalia

• The organisms of Animalia kingdom are all organisms which are multicellular eukaryotes without cell walls.

• Organisms of Animalia kingdom are heterotrophs.