Question

Cyanobacteria and heterotrophic bacteria have been clubbed together in Eubacteria of kingdom Monera as per the “Five Kingdom Classification” even though the two are vastly different from each other. Is this grouping of the two types of taxa in the same kingdom justified? If so, why?

Answer 1

Introduction

Five kingdom classification is based on

• Structure of cells
• Unicellular or multicellular organisation.
• Mode of nutrition
• Phylogenetic relationship

Different features

Cyanobacteria are autotrophic as they show oxygenic photosynthesis whereas heterotrophic bacteria depend on other organisms for food.

Common features

The following features are common among both the taxa:-

• Cell wall- Both have outer rigid cell walls with peptidoglycan.
• Nucleoid- Both have naked DNA molecules, it's circular with no free end.
• Unicellular- Both are unicellular prokaryotes.

Justification

The grouping is justified as cyanobacteria and heterotrophic bacteria have common features so these are clubbed under Eubacteria of the kingdom Monera.