The article "How Many Species Are There on Earth and in the Ocean?" by Camilo Mora et al. addresses the fundamental question of how many species inhabit Earth. The authors present a method to estimate the total number of species in all domains of life, based on the consistent pattern in higher taxonomic classification. They compiled data on approximately 1.2 million valid species and found that higher taxonomic ranks are more completely described than lower levels. By fitting asymptotic regression models to the temporal accumulation curves of higher taxa, they predicted the total number of species for 18 taxonomic groups and all eukaryote kingdoms. Their approach estimated a global total of ~8.7 million eukaryotic species, with ~2.2 million marine species. Despite 250 years of taxonomic classification and over 1.2 million species already cataloged, the authors suggest that 86% of existing species on Earth and 91% in the ocean still await description. They emphasize the need for renewed interest in exploration and taxonomy to close this knowledge gap, especially given the high extinction rates. The study highlights the importance of robust extrapolation methods and the potential for future improvements in data quality to enhance estimates of global species richness.The article "How Many Species Are There on Earth and in the Ocean?" by Camilo Mora et al. addresses the fundamental question of how many species inhabit Earth. The authors present a method to estimate the total number of species in all domains of life, based on the consistent pattern in higher taxonomic classification. They compiled data on approximately 1.2 million valid species and found that higher taxonomic ranks are more completely described than lower levels. By fitting asymptotic regression models to the temporal accumulation curves of higher taxa, they predicted the total number of species for 18 taxonomic groups and all eukaryote kingdoms. Their approach estimated a global total of ~8.7 million eukaryotic species, with ~2.2 million marine species. Despite 250 years of taxonomic classification and over 1.2 million species already cataloged, the authors suggest that 86% of existing species on Earth and 91% in the ocean still await description. They emphasize the need for renewed interest in exploration and taxonomy to close this knowledge gap, especially given the high extinction rates. The study highlights the importance of robust extrapolation methods and the potential for future improvements in data quality to enhance estimates of global species richness.