explore the key events and developments that occurred during the Devonian Period, including the diversification of fish species, the colonization of land by plants and early amphibians, and significant geological transformations. The article aims to provide a comprehensive overview of the biological and environmental changes that shaped life on Earth during this time, making it a valuable resource for readers interested in paleontology, geology, and evolutionary biology.

The main keyword, “What happened 400 million years ago,” addresses the search intent of users looking for historical information about significant events in Earth’s geological past. The content offers detailed insights into the Devonian Period, highlighting its importance in the evolutionary timeline and the development of ecosystems, which can attract an audience interested in science and history. This article would be a great addition to a website focused on educational content, science, or history, appealing to both casual readers and enthusiasts seeking in-depth knowledge.