Overview
This excerpt summarizes the fundamentals of biological classification covered in the NEET Biology Handbook, focusing on Whittaker's five kingdom system, the three-domain system, and types of bacteria.
Biological Classification Systems
- Robert Whittaker proposed the five kingdom classification: Monera, Protista, Fungi, Plantae, and Animalia.
- Each kingdom is defined by its unique characteristics such as cell type, nutrition, and body organization.
- The three-domain system divides Monera into two domains: Archaebacteria and Eubacteria.
Bacterial Classification
- Bacteria in the kingdom Monera are classified as Gram-positive or Gram-negative based on cell wall composition.
- Gram-positive bacteria have thick peptidoglycan walls; Gram-negative have thinner walls with an outer membrane.
- Examples of bacterial classification help distinguish their structural and functional traits.
Key Terms & Definitions
- Kingdom — Highest taxonomic group below domain, grouping organisms by fundamental traits.
- Monera — Kingdom of prokaryotic organisms including bacteria.
- Protista — Kingdom of mostly unicellular eukaryotic organisms.
- Fungi — Kingdom of eukaryotic organisms with chitin cell walls, absorbing nutrients.
- Plantae — Kingdom of multicellular, photosynthetic eukaryotes.
- Animalia — Kingdom of multicellular, heterotrophic eukaryotes.
- Archaebacteria — Domain/kingdom of prokaryotes with unique cell membranes, often living in extreme environments.
- Eubacteria — Domain/kingdom of "true bacteria" with typical cell walls.
- Gram-positive — Bacteria with thick cell wall staining purple in Gram stain test.
- Gram-negative — Bacteria with thin cell wall and outer membrane, staining pink/red.
Action Items / Next Steps
- Review the detailed characteristics of each kingdom for NEET exam preparation.
- Memorize the differences between Gram-positive and Gram-negative bacteria.
- Study examples of each kingdom and domain classification.