Paleozoic Time
About the Paleozoic Era The Paleozoic Era also known “The Age of Life”, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another. Plants became widespread. And the first vertebrate animals colonized land. The Climate and Changes to Shape and Location of the Continent After the Ordovician Period came the Silurian Period (443 million years ago to 416 million years ago), which saw the spread of jawless fish throughout the seas. Mollusks and corals also thrived in the oceans, but the big news was what was happening on land: the first undisputed evidence of terrestrial life. This was the time when plants evolved, though they most likely did not yet have leaves or the vascular tissue that allows modern plants to siphon up water and nutrients. During the Paleozoic period, shifting of the Earth's tectonic plates caused the formation of supercontinents. Ferns appeared, as did the first trees. At the same time, the first vertebrates were colonizing the land. Major Changes in the Landforms Believed to be the highest mountain range around 466 mya (million years ago), the Appalachian Mountains stretch from the island of Newfoundland to central Alabama. In the earliest Paleozoic era, the Appalachians were a passive plate margin and periodically submerged beneath shallow seas. The Appalachian Mountains formed when a neighboring oceanic plate collided and began to sink beneath the North American craton (an old, stable part of a continent). motions of the plates changed during the early Paleozoic era and began the mountain-building tectonic collisions during the Paleozoic era. Major Changes in the development of living things The Paleozoic began with the Cambrian Period, best known as explosion of life on Earth. This "Cambrian explosion" included the evolution of arthropods and chordates. In the Paleozoic Era, life flourished in the seas. After the Cambrian Period came the 45-million-year Ordovician Period, which is marked in the fossil record by an abundance of marine invertebrates. Perhaps the most famous of these invertebrates was the trilobite, an armored arthropod that scuttled around the seafloor for about 270 million years before going ext inct. Why the Paleozoic Era Ended Ended with the world's largest mass-extinction known to man. The causes of these great events are currently unknown and under debate. |