Biology Notes: Floral Diversity, 5-Kingdom Classification, Domains, and Nepal Flora

Floral diversity

• Definition: The distribution and abundance of plant life in a particular geographic region at a certain time is called floral diversity.

5-Kingdom classification (Whittaker, 1969)

• Five kingdoms: Monera, Protista, Fungi, Plantae, Animalia.
• Criteria for proposing the system:
  • cellular organization
  • body organization
  • nutrition
  • evolutionary history/relationships
• Representation (from the transcript):
  • Monera: all prokaryotic organisms
  • Protista: unicellular and some simple multicellular eukaryotes
  • Fungi: non-photosynthetic; saprophytes
  • Plantae: multicellular producers
  • Animalia: multicellular consumers

Merits of the 5-kingdom system

• All prokaryotic organisms are separated from eukaryotes
• Unicellular and eukaryotic organisms are grouped under Protista
• Non-photosynthetic fungi are separated from other groups and placed under Mycota
• Basis includes complexity of cellular organization, body organization, mode of nutrition, etc.
• Reflects evolutionary history/relationships among groups
• It is a well-accepted system of classification

Domains of life

• The term domain was coined by Carl Woese
• Domain: the highest taxonomic category above kingdom
• 3 Domains: $ext{Archaea}, ext{Bacteria}, ext{Eukarya (Sukarya)}$
• Monera is split into two domains: $ext{Archaea}$ and $ext{Bacteria}$
• The remaining four kingdoms (Protista, Mycota/Fungi, Plantae, Animalia) are kept under Domain $ext{Eukarya}$

Domain Archaea

• Includes most primitive prokaryotic organisms
• Found in extreme environments (e.g., hot springs)
• Cell wall is not made of peptidoglycan

Domain Bacteria

• Unicellular prokaryotes
• Nucleus is not bounded by a membrane
• Membrane-bound organelles are absent
• Cell wall is made of peptidoglycan (mucopeptide)
• Ribosomes are of the $70S$ type

Domain Eukarya

• Includes the kingdoms Protista, Mycota (Fungi), Plantae, Animalia
• Organisms have a nucleus and membrane-bound organelles

Status of flora in Nepal

• Nepal covers $0.1\%$ of the total land area on Earth
• It comprises $3.2\%$ of world biodiversity
• Global biodiversity rank: $27^{th}$ in the world
• In Asia: $10^{th}$ position
• In South Asia: $8^{th}$ position
• Taxa present:
  • Angiosperms: $6973$ species
  • Fungi: $2467$ species
  • Bryophytes: $1213$ species
  • Algae: $1001$ species
  • Lichens: $850$ species
  • Pteridophytes: $580$ species
  • Gymnosperms (hymnosperms in the transcript): $41$ species
• Lichens: a symbiotic association between algae and fungi; the composite organism is called a lichen.