Life on Earth Died Long Before Dinosaurs Dominated the Planet

They were the largest land animals that ever roamed the Earth. Dinosaurs inhabited most of Earth’s landmass before going extinct about 65 million years ago.   

Dinosaurs had an extraordinary history. They lived about 160 million years as the dominate life forms on the planet. They became extinct after a major climate change affected Earth. But an even larger earth-wide extinction wiped out most life forms about 90 million years before dinosaurs walked the planet. Nearly all life on Earth disappeared during a period called The Great Dying.

About 252 million years ago, give or take a million years, most terrestrial vertebrates (air breathing animals with spines) disappeared from Earth. It’s dubbed The Great Dying because at least 70 percent of land animals and 96 percent of all marine species died.  

Officially known as the Permian-Triassic (PT) Extinction event, it predated the existence of dinosaurs by millions of years. The PT theory was often ridiculed by the scientific community when it was first discussed by paleontologists in the 1950s. However, evidence supporting the PT explanation was found starting in the year 2000 when geologists began digging through five volcanic ash beds discovered in Meishan, China.

The ash beds continue to provide scientists with evidence to explore the carbon cycles captured in ancient rock formations and lava flows buried deep inside the earth’s crust. Archeologists find concentrations of iridium inside the ancient layers of ash during digs that are relatively new at the China location. Iridium is an element rare to the Earth’s surface but contained in high amounts in comets, meteors, and old volcano eruptions.

Pangaea: Gigantic land mass
before the continents separated

The rare element’s concentration inside the newly found excavated sites dates to the PT period, giving credibility to the often disputed theory that the large extinction did happen.

Evidence from lifeforms that existed at the time of the PT disappeared long ago. Scientists think small animal life forms, even some mammals, existed. But that’s speculation and is nothing more than guessing.   

In theory, the PT event resulted from severe damages to the Earth’s atmosphere from the eruption of hundreds of volcanoes as well as numerous comet and meteor impacts on the Earth. The atmosphere became so polluted that sunshine was blocked from hitting the earth, causing continuous darkness for hundreds of thousands of years.

Oxygen levels in the air slowly depleted, stopping the biological life cycle of plants; the food chain stopped, and animals died off.      

Scientists describe the PT as an event. In scientific terms, the time required for the climate changes to cause The Great Dying could cover a million years or more. Most people can’t relate to the meaning of such a long time as it’s described by experts of geology. An event for most people is a relatively short period of time for a particular occurrence, not a time period that could be more than one million years.     

The ravages to the air and environment increased because Earth’s land mass consisted of a single supercontinent during the Permian era. Called Pangaea, that huge land mass included all the ground areas we identify today as Earth’s seven continents. Pangaea didn’t start to break up until half way into the Triassic period (when dinosaurs flourished) about 175 million years ago.

The size of the single continent contributed to the massive extinction by disrupting the circulation of seawater, making oceans stagnant. This caused a depletion of oxygen in seawater. Sea creatures died, eliminating about 96% of the ocean life.    

Digging in volcano layers
in Meishan, China

Peter Ward, a geologist respected for his work in studying fossils, has studied rock layers from the Permian and Triassic periods. His findings show an abundance of animal fossils in the time up to the end of the Permian period. But throughout the first half of the Triassic period, Ward found very few fossils. He concludes that the lack of recorded life between the two periods proves that The Great Dying occurred about that time 252 million years ago. It was the most catastrophic extinction that killed off Earth’s reptiles, amphibians, insects and plants, according to Ward.

Evidence about The Great Dying remains meager and makes most of the reports about that period strictly speculation. Before the geological findings in China, the idea of the world’s biggest extinction was not accepted as a scientific fact. More discoveries will undoubtedly surface from the China digs and from the hands-on research from determined geologists such as Ward. 

Physical discoveries as basic as skeletons and thousands of fossils have given geologists accurate evidence about the years dinosaurs dominated the earth. Studying chemical residue among Earth’s layers is the only way scientists can find evidence about The Great Dying. The physical evidence disappeared during the more than 200 million years since that cataclysmic event of Earth’s history happened.