Estimating Numbers of Species
- Current global species estimates vary, but it is generally accepted that there are between 5 and 10 million species on Earth
- As of December 2022, just over 2.16 million species have been described and classified
- However, the actual number of species could be higher or lower depending on a variety of factors, including classification issues, under-sampling of certain groups, and differences in taxonomic opinions
Challenges of Estimating Species Numbers
- Estimates of the total number of species on the planet vary considerably due to a number of factors, including:
- Classification issues
- Lack of funding for scientific research
- Limited access to remote and inaccessible habitats
- The classification of species is not always clear-cut, and different taxonomists may have different opinions on what constitutes a species
- As a result, there may be significant variation in the number of species recognised within a particular group
- Additionally, the discovery of new species can lead to changes in classification, which can further complicate the process of estimating the total number of species
- Another factor that contributes to the variation in global species estimates is the limited funding for scientific research
- Many areas of the world remain relatively unexplored, and new species are still being discovered in remote and inaccessible habitats
- Without adequate funding for research and exploration, many of these species may go undiscovered and unrecorded, making it difficult to estimate the total number of species on the planet
- In addition, some groups of organisms are more difficult to study than others, which can result in a significant underestimation of the total number of species within those groups
- For example, the diversity of microorganisms is poorly understood, and many species have yet to be discovered and described
- Similarly, deep-sea organisms are significantly under-sampled
Pie chart showing the estimated proportions of different groups of organisms on Earth today, by numbers of species