The Cambrian Explosion is a sudden appearance in the fossil record of complex animals that had mineralized skeletal remains. This is considered to be the most important evolutionary event in the history of life on Earth. 96% of species became extinct after the Permian mass extinction. There were at least two or more phases of extinction over the span of millions of years. This was the the insect population's one and only mass extinction. This tragic event may have been caused by an asteroid impact or a drop in oxygen levels. 65 million years ago, the dinosaurs died in Cretaceous mass extinction. This mass extinction may have been caused by flood basalt eruptions affecting the world's climate, and a drastic fall in sea level.
The Earth is approximately 4.543 billion years old. The Silurian Extinction happened 439 million years ago. Dinosaurs lived between 230 and 65 million years ago in the Mesozoic Era. This was millions of years before the first homo sapien appeared. Modern humans evolved 200,000 years ago. Compared to the Earth, humans are a relatively new species. If the timeline of Earth was based off a one year calendar with the Big Bang occurring on January 1, humans have only been around for about five minutes. I was surprised that we have impacted the world so much in the five minutes that humans have been on the Earth.
The last 200,000 years have been mainly dominated by humans. In the past 50 years, humans have burned tons and tons of fossil fuels. The human society has also dumped massive amounts of trash into landfills and oceans. With all the technologies we have created to change the Earth for the better, we have dumped so much waste that the Earth might never recover.
My question is "How do scientists know what happened in every mass extinction?"
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| Earth life in 24 hours |
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