Global Biodiversity

Global biodiversity refers to the sum total of the variety and variability of all living organisms on Earth. It encompasses the complete range of biological organization across the entire biosphere. The term "biodiversity" was popularized by the sociobiologist Edward Wilson to describe this combined diversity, which is conventionally studied at three fundamental levels:

Representing global biodiversity: Proportionate number of species of major taxa of plants, invertebrates and vertebrates

Despite centuries of scientific documentation, a large proportion of Earth's species remain undiscovered, making "global biodiversity" one of the most debated estimates in ecology.

• According to the IUCN (2004), slightly more than 1.5 million species of plants and animals have been formally described worldwide.
• Because this number represents only the documented fraction of life on Earth, ecologist Robert May proposed a more conservative and scientifically sound global estimate of about 7 million species.

Among the species that have been formally recorded:

• Animals make up more than 70% of all described species
• Plants account for more than 22% of described species
• Insects alone constitute 61% of all animal species – making them the single largest group within the animal kingdom

Estimating prokaryotic (bacterial and archaeal) diversity is exceptionally difficult because:

• Conventional taxonomic methods (morphology-based classification) are inadequate for distinguishing microbial species.
• Molecular and biochemical criteria suggest that prokaryotic diversity could run into millions of species, far exceeding visible plant/animal diversity.

• Global biodiversity, a term popularised by Edward Wilson, refers to the total variety of life on Earth and is studied across three fundamental levels: genetic, species, and ecological.
• While the IUCN (2004) formally records slightly over 1.5 million described species, ecologist Robert May conservatively estimates the true global total to be approximately 7 million.
• Animals dominate the documented species list, comprising over 70% of all recorded life on Earth.
• Insects are the single most diverse taxonomic group, constituting 61% of all described animal species.
• Plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) account for no more than 22% of all formally described species.
• Prokaryotic diversity remains unknown because conventional taxonomic methods cannot identify them; however, molecular and biochemical criteria suggest microbial species could number in the millions.