The Silurian is a geological period that occurred approximately 443 to 419 million years ago, following the Ordovician and preceding the Devonian. It is characterized by significant changes in the Earth's climate and the development of diverse marine life, including the first coral reefs and the rise of jawed fish. During the Silurian, land plants began to emerge, marking a crucial step in the evolution of terrestrial ecosystems. The period also saw the appearance of early terrestrial arthropods, such as millipedes and scorpions, which adapted to life on land.