Biological Classification: Characteristics of Monera and Protoctista Kingdoms
Kingdom Monera: Prokaryotic Microorganisms
Monera are prokaryotic, unicellular microorganisms, sometimes forming agglomerations or filamentous structures (like certain Cyanobacteria).
Key Characteristics of Monera
- Reproduction: They reproduce asexually.
- Nutrition: Varied, including heterotrophic (saprophytic) and autotrophic species.
- Metabolism: Varied, including anaerobic and aerobic species.
Metabolic Classification of Bacteria
- Aerobic and Autotrophic Bacteria: Cyanobacteria and green bacteria.
- Chemotrophic Bacteria: Obtain energy by oxidizing molecules, e.g., colorless sulfur bacteria.
- Heterotrophic Bacteria (Saprophytic): Decomposers.
Morphology and Types of Bacteria
Bacteria exhibit varied morphology:
- Cocci (spherical)
- Rods (cylindrical)
- Vibrios
- Spirilla (curved)
1. Eubacteria (True Bacteria)
Eubacteria are classified into types based on their cell wall structure and metabolism:
- Gram-Positive Eubacteria: Are heterotrophic and often form endospores.
- Gram-Negative Eubacteria: Can be heterotrophic or autotrophic.
Mycoplasma
These are the smallest bacterial cells, lacking a cell wall. For example, Mycoplasma pneumoniae causes pneumonia.
2. Archaebacteria (Archaea)
Archaebacteria have a typical prokaryotic organization but possess structural characteristics (cell wall and membrane composition) and metabolic features that differentiate them from Eubacteria.
They develop in extreme living conditions:
- Methanogens
- Extreme halophiles
- Thermoacidophiles
Kingdom Protoctista (Protista)
Protoctists are eukaryotes that lack differentiated tissues. They are typically unicellular or colonial, though some exhibit simple multicellular organization. They live in aquatic or humid environments.
General Features of Protoctista
- Nutrition: Can be autotrophs or heterotrophs.
- Reproduction: Can be sexual or asexual.
1. Protozoa (Heterotrophic Protoctists)
Protozoa are unicellular organisms characterized by heterotrophic nutrition. Asexual reproduction occurs via bipartition, multiple fission, or sporulation.
Forms of Locomotion
Protozoa use various methods for movement:
- Cilia or flagella
- Pseudopodia
- Flexion of the cell
Classification of Protozoa by Locomotion and Ecology
Protozoa are classified into major groups based on their form of locomotion: