Browsing the "Devonian" Category

The Devonian period is a division of earth’s history spanning from around 419 to 359 million years ago, and during which vertebrates became far more ecologically diverse. The Devonian is often called the age of fishes owing to their abundance and diversity during this period. The Early Devonian is characterised by the jawless armoured ostracoderm fish. Later, these were largely replaced by jawed fish such as placoderms, some of which reached over 9 meters in length and were the top predators of their day. The land was transformed by the evolution of the first forests. At the same time, lobe-finned fish began to evolve limbs, a rigid skeleton and increased air breathing capabilities, gradually leaving the water to become the first land-living vertebrates. The Devonian was a tectonically active period in which the continents began to drift together. It had a relatively warm climate and consequently the planet probably lacked ice caps. The end of the Devonian is marked by a mass extinction event.