The study presents a comprehensive synthesis of the Tree of Life (TTOL) based on 2,274 studies and 50,632 species, aiming to understand the patterns and rates of diversification and speciation. The authors found that species diversity has been expanding overall, with constant diversification rates in eukaryotes. They identified and avoided biases in previous analyses, such as low taxon sampling, small clade size, and the inclusion of stem branches. The time-to-speciation (TTS) was consistently around 2 million years across different groups, suggesting that speciation is dominated by random events rather than adaptive change. The results support a model where speciation is driven by the buildup of genic incompatibilities during geographic isolation, leading to reproductive isolation and eventual species formation. The findings highlight the importance of understanding the temporal relationship between speciation and adaptation, suggesting that they are decoupled processes.The study presents a comprehensive synthesis of the Tree of Life (TTOL) based on 2,274 studies and 50,632 species, aiming to understand the patterns and rates of diversification and speciation. The authors found that species diversity has been expanding overall, with constant diversification rates in eukaryotes. They identified and avoided biases in previous analyses, such as low taxon sampling, small clade size, and the inclusion of stem branches. The time-to-speciation (TTS) was consistently around 2 million years across different groups, suggesting that speciation is dominated by random events rather than adaptive change. The results support a model where speciation is driven by the buildup of genic incompatibilities during geographic isolation, leading to reproductive isolation and eventual species formation. The findings highlight the importance of understanding the temporal relationship between speciation and adaptation, suggesting that they are decoupled processes.