- Examples: Bacteria, actinomycetes Filamentous bacteria), Cyano bacteria (Blue green algae)
b) Cyanobacteria (Blue green algae)
c) Archaebacteria (Ancient bacteria)
- They are commonly found in water, air, soil, and on living and dead organic matters.
- Archae bacteria (ancient bacteria) live under extreme environmental conditions like high temperature(800C) , high salt conditions and in the absence of oxygen etc.
- They are microscopic without nucleus and other membrane bound organelles. Most of them have a rigid cell wall.
- Bacteria show two types of nutrition: Autotrophs and Heterotrophs
- They prepare food materials using light energy (photo autotrophs) or energy released from chemical reactions (Chemoautotrophs)
- Heterotrophic bacteria may be parasitic, saprophytic and symbiotic in nature.
- Asexual methods (Binary Fission, Endospore formation).
- Sexual Methods (Conjugation, transformation, Tranduction)