When the oceans died and life changed forever

Around 445 million years ago, the Late Ordovician Mass Extinction caused a rapid climate collapse that devastated ocean life. This event, characterized by the spread of massive glaciers and a shift to an icehouse climate, wiped out 85% of marine species. However, jawed vertebrates, which survived in isolated marine refuges, gained an advantage and diversified into many forms. This ancient reset significantly influenced the evolution of life on Earth, leading to the dominance of jawed vertebrates in modern marine ecosystems.