Final answer
Approximately 99.9% of species that have existed over the past 500 million years are currently extinct.
Step-by-step explanation
The calculation for the percentage of extinct species involves considering the total number of species that have ever existed and comparing it to the number of species still present today. Fossil records and estimations from paleontologists provide insights into the diversity of life throughout Earth's history. With millions of years of evolution, the vast majority of species that once populated the planet have ceased to exist. By subtracting the current number of known living species from the total estimated historical species and expressing this as a percentage, we arrive at the striking figure of 99.9%.
This high percentage emphasizes the dynamic nature of Earth's ecosystems and the constant evolution of life forms. Various factors, including environmental changes, natural disasters, and competition for resources, contribute to the continuous turnover of species. Extinction is a natural part of the evolutionary process, shaping the biodiversity we observe today.
Understanding the magnitude of extinction events over such a vast timespan helps underscore the resilience and adaptability of life on Earth. It also highlights the importance of conservation efforts to protect the existing biodiversity and address human-induced threats that could accelerate the extinction rate.