Halfway into the Triassic Period things were going pretty well again. Speculation is that the comet struck the ocean and that the actual crater has disappeared due to plate tectonics.
Evidence of this has been found in layers of rock dating from 250 million years ago. Just recently, scientists have discovered evidence that this extinction was caused by a comet impact, possibly in the single ocean that covered most of the Earth at the time. This was the greatest extinction event yet discovered in the history of our planet. Earthquakes could have changed the courses of rivers, cut off migration routes, and created other barriers that would have drastically changed the Earth's ecosystems. Undersea volcanoes could have changed the chemistry of water, making it poisonous for sea life. Volcanoes on land would have created great clouds of dust and particles in the atmosphere that could block sunlight for years, killing plants and disrupting the food chain. This could have been a combination of volcanoes and earthquakes. There seems to be general agreement that this particular event, because it was so widespread, was caused by massive geologic activities. Some, such as sharks and Mammal-Like Reptiles, eventually came back.Įxtinction events occur repeatedly throughout Earth's history, and there is much debate about the causes of specific extinctions. Many, such as trilobites, disappeared forever. This included plants, fish, and land animals. Something happened, a catastrophic event, which killed off more than 80% of ALL the living things on the Earth. In the seas, life was flourishing as well with sharks and sea-dwelling reptiles, ammonites, and many kinds of fish and plants. Predators as big as modern bears and plant-eaters almost as big as modern elephants began to roam the land. The largest creatures on land were the Mammal-Like Reptiles, some of which were huge. Plant life was varied and animal life had developed to fill many different areas of the environment.
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