The Paleozoic Era: A Time of Life's Explosive Growth and Massive Extin

By: Efe Baran Erdogan

The Paleozoic Era: A Time of Life's Explosive Growth and Massive Extinction

Phanerozoic Eon's Paleozoic Era (541 to 252 million years ago)

The Paleozoic Era saw an explosion of new life forms due to several interconnected factors. The most prominent factor seems to be oxygen levels. Volcanic activity and such played a part in it aswell. This cycle of adaptation and extinction lead to severe biodiversity. And also, the landmass went on to form a super continent, which was pretty sick.

A large series of extinction and biodiversity events took place during this time, and with it was introduced many things we are familiar with today, such as ECOSYSTEMS, and fish, and sharks, and fungi, and plants, and yea.

• Paleozoic era- First era of our current eon. It was 541-252 million years ago
• Cambrian period- 541-485.4 million years ago
• The Cambrian explosion- the burst of evolutionary innovation during the Cambrian period
• Cambrian Ordovician extinction event- The extinction of many species, some of which where introduced in the Cambrian explosion
• Ordovician period- 485.4 to 443.8 million years ago, was another burst in diversity
• Silurian period- 443.8 to 419.2 million years ago
• Devonian period- 419.2 to 358.9 million years ago
• Carboniferous period- 358.9 to 298.9 million years ago
• Permian period- 298.9 to 251.902 million years ago

Timeline and events in more detail

The Climate was warm and mostly tropical. Sea levels were high, covering much of the land in shallow, warm seas. There were no polar ice caps, which created a greenhouse-like environment. The atmospheres oxygen levels began rising due to the rise of the phytoplankton and early plants, which led to more complex organisms. CO2 levels were still relatively high. During this time, most of the land was divided into smaller continents. The seas dominated, with many continental shelves. The Cambrian Explosion brought an incredible variety of marine life, including trilobites, brachiopods, mollusks, and the first vertebrates (jawless fish). Reefs began forming, and early arthropods appeared.

Early Paleozoic (Cambrian to Ordovician)

The climate is relatively still warm, but more temperate in some areas. Shallow seas persisted, and the first signs of glaciers in high-latitude regions appeared near the end of this period. The atmospheres oxygen levels continued to increase, allowing for the evolution of larger animals and plants. CO2 levels began to drop as plants colonized land. Continents like Gondwana and Euramerica were forming, leading to shallower seas, which facilitated the spread of life onto land. This period saw the rise of early vascular plants and the first forests. Insects and arachnids also made their way onto land. Marine life continued to diversify with the appearance of jawed fish and early sharks.

Mid-Paleozoic (Silurian to Devonian):

The late Paleozoic saw significant climate shifts. The Carboniferous period was warm and humid, ideal for vast tropical forests. However, as the Permian began, the Earth entered an ice age with cooler, drier climates and glaciation at the poles. The oxygen levels were at their peak during the Carboniferous, allowing for enormous insects like dragonflies with wingspans of over two feet. However, as forests declined in the Permian, oxygen levels began to drop. Pangea, the supercontinent, formed by the late Permian. This created vast deserts in the interior of the continent, due to the difficulty of moisture reaching the inner regions. The Carboniferous was dominated by large swamps and forests filled with ferns and giant trees. Tetrapods began laying amniotic eggs on land, and reptiles diversified. The Permian saw reptiles and early mammal-like creatures dominate the land, as well as the collapse of many ecosystems.

Late Paleozoic (Carboniferous to Permian):

Occurred approximately 252 million years ago at the end of the Paleozoic Era, marking the boundary between the Permian and Triassic periods. It was the largest and most severe extinction event in Earth’s history, resulting in the loss of approximately 96% of marine species, and 70% of terrestrial species. It was caused by many factors, major ones including oxygen levels and volcanic activity.

The massive loss of life caused entire ecosystems to collapse both in the oceans and on land. Coral reefs, which were once flourishing, disappeared for millions of years. The extinction cleared the way for new life forms to evolve, particularly in the Mesozoic Era, which became the the time of the DINOSAURS. It took nearly 10 million years for biodiversity to recover from this event, making it one of the slowest recoveries from an extinction in Earth's history.

Permian-Triassic Extinction Event

Some Interesting Facts of Note: Cambrian Explosion: Life forms with hard shells and skeletons first appeared, giving rise to major animal groups we know today. First Vertebrates: The first fish evolved, marking the beginning of complex vertebrate life. The Formation of Pangea: Continents gradually merged, forming a supercontinent by the late Paleozoic. Shark Evolution: The Paleozoic saw the evolution of early sharks, which became dominant predators and movie stars due to their jaws. First Forests: Huge forests appeared, contributing to high oxygen levels, which allowed for large insects. The Paleozoic Era was marked by a dynamic climate characterized by repeated transitions between glacial and interglacial conditions, which influenced both terrestrial and marine ecosystems. (Haq & Schutter, 2008) The late Paleozoic Ice Age was the longest-lived ice age in the Phanerozoic Eon, lasting for millions of years and leading to significant changes in Earth's climate and ecosystems (Montañez & Poulsen, 2013)

So, in Conclusion:

RESOURCES: All images are stock images. PBS Eons. (2020, March 16). From the Cambrian explosion to the Great Dying [Video]. YouTube. https://www.youtube.com/watch?v=RDQa0okkpf0 Montañez, I. P., & Poulsen, C. J. (2013). The late Paleozoic ice age: An evolving paradigm. Annual Review of Earth and Planetary Sciences, 41, 629-656. https://doi.org/10.1146/annurev.earth.031208.100118 Haq, B. U., & Schutter, S. R. (2008). Chronology of Paleozoic sea-level changes. Science, 322(5898), 64–68. https://doi.org/10.1126/science.1161648

The Paleozoic Era was a time of evolutionary innovation, the rise of diverse ecosystems, and significant extinction events that reshaped life on Earth. It set the foundation for the age of dinosaurs and beyond.