Definition

Noun: - A major biological kingdom: Kingdom Monera is a historical taxonomic classification encompassing all prokaryotic organisms. This includes bacteria, cyanobacteria (blue-green algae), and archaea. These organisms are characterized by the absence of a membrane-bound nucleus and other complex organelles.

Usage Notes

• Scientific Context: The term "Kingdom Monera" is primarily used in historical and educational contexts to describe the classification of prokaryotes. In modern taxonomy, this group is often divided into two distinct domains: Bacteria and Archaea.
• Informal Divisions: Due to the vast diversity and challenges in classifying prokaryotes into standard phyla, major groups within Monera are often referred to by informal, descriptive names (e.g., cyanobacteria, mycoplasmas, rickettsias).

Examples

• In older biology textbooks, Kingdom Monera included all single-celled organisms without a nucleus.
• The study of Kingdom Monera is fundamental to understanding microbiology and the origins of life.
• Scientists have re-evaluated the classification of Kingdom Monera, leading to the three-domain system.

Advanced Usage

• "The kingdom of prokaryotes": A descriptive phrase synonymous with Kingdom Monera.
  • The kingdom of prokaryotes, once called Monera, is now split into two domains.

Variants and Related Words

• Monera (n): The singular form, often used interchangeably with "Kingdom Monera."
  • Monera represents the most ancient forms of life on Earth.
• Prokaryote (n): An organism belonging to Kingdom Monera; a cell lacking a nucleus.
  • Bacteria are a type of prokaryote.
• Eubacteria (n): A major division within Monera, referring to "true" bacteria.
• Archaebacteria / Archaea (n): A division of prokaryotes distinct from eubacteria, now classified as a separate domain.

Synonyms

• Prokaryotae: An alternative taxonomic name for the kingdom.
• The prokaryotic kingdom: A descriptive synonym.

Noun

1. prokaryotic bacteria and blue-green algae and various primitive pathogens; because of lack of consensus on how to divide the organisms into phyla informal names are used for the major divisions