Catastrophe of life

  Droughts, epidemics, and yellow sand in the sky, and even the last corn of mankind, face the danger of being swept by sandstorms… In the Hollywood blockbuster “Interstellar”, the scene of the end of the earth makes people’s minds sinking. In the movie, as the natural environment deteriorates, most species have become extinct. Even if human beings create ultra-highly intelligent robots, they are unable to restore the vibrant home of the earth. If the earth is doomed, so life go ……
  Earth: Cast Away
  violent nature
  of volcanic eruptions, glacial fell, meteorite landed …… violent blow from nature to make life on Earth, no place to hide. However, as long as the diversity of life still exists, even if it becomes a barren land, life will always make a comeback.
  Krakatau Island is a volcanic island located in the strait between the islands of Java and Sumatra, Indonesia. When the weather is clear, you can see its shadow from the west coast of Java Island. Although this island is not big, it has experienced the most spectacular volcanic eruption on earth since human history.
  On August 27, 1883, Krakatau volcano began to erupt, and the violent explosion sound could be heard 560 kilometers away in Jakarta. The rubble and dust from the volcano rolled in the air, and the sky was pitch black within 400 square kilometers. The eruption of the volcano also caused earthquakes and tsunamis. The huge tsunami set off waves of more than 40 meters high, and it spread to Colombo, the capital of Sri Lanka, 2,800 kilometers away, and Mumbai, the second largest city in India, 4,300 kilometers away.
  The ash cloud produced by the volcanic eruption remained in the air for two years, causing unusual phenomena in many parts of the world. In the Seychelles, the sun is like a sunset in the fog, and the sky is fiery red. In South America, the sun that people see is blue. In Panama and Honolulu, people can enjoy the green sunset for months.
  The violent eruption of the volcano made the entire Krakatau island a barren land, and life disappeared.
  However, it was on such a severely damaged island that slowly, life appeared and the ecosystem began to rebuild. The recovery of the volcanic island has given scientists a golden opportunity to observe the restoration of the ecosystem. In the 9th month after the outbreak, an expedition came to the island, where only one spider was weaving a web. Six years later, when scientists returned to the island, they found spiders, flies, beetles, butterflies, and even lizards, and they probably came to the island. More than 20 years later, there are already trees as high as 12 meters on the island. Scientists are delighted to see that in less than 100 years, the ecology of the island has been completely restored, and the species is more abundant, including more than 400 tubular plants, 54 butterflies, 30 birds, 18 terrestrial molluscs, and 17 bats. Nine kinds of reptiles, even on the steep mountain, you can see trees and vines growing lushly for the limited space.
  So, how did life return to the island? The land on the volcanic island is nascent, and it is impossible to have ungerminated seeds from the soil. Therefore, the seeds of all the plants on the island are either drifting from the sea or flying with the wind.
  The flourishing of early plants provided the foundation of the island’s life food chain. Those who occasionally pass by fruit-feeding birds and bats leave behind plant seeds from other places. They take root, germinate, grow, and bear fruit in the right place and in the right climate, which in turn attracts more Birds and bats come to forage. The more animals come, the faster the cycle and the faster the increase in plant species, which attracts more foraging animals. In 1980, there were 26 species of plants spreading seeds on the island by animals, 58 species spread by ocean currents, 25 species spread by wind, and 16 species of plants were brought by tourists or explorers. By 1990, there were 130 species of plants and 43 species of birds on the island, of which 38 species settled there. In the early years, the main species of birds on the island were insectivorous birds and seabirds. With the expansion of plant communities and the increase in the number of birds, carnivorous birds appeared, and the appearance of carnivorous birds perfected the food chain.
  The process of reconstruction of Krakatau’s ecosystem tells us that biodiversity is a key factor in maintaining our world. As long as biodiversity still exists, even if it becomes a barren land, life will always come back.
  Large-scale volcanic eruptions like Krakatau must have occurred repeatedly in a long geological age, and Krakatau’s eruption is obviously not the largest. In fact, the largest and most serious disaster in the history of the earth occurred about 250 million years ago. This is the so-called “Permian Mass Extinction”. It is even more terrifying than the well-known extinction of the KT world. In that mass extinction, dinosaurs disappeared from the earth forever.
  On the Earth’s continent in the Permian period, we can see all kinds of strange animals everywhere, such as the two-dented beast and the spleen, which rule the earth. However, at the end of the Permian, more than 90% of the species on the planet were extinct. What caused the mass extinction of organisms in the Permian Period? Scientists have different opinions. One of them is the theory of super volcanic eruption.
  The theory of super volcanic eruption believes that due to the eruption of super volcanoes, a “wall of fire” as high as 1,600 meters and stretching for thousands of kilometers was formed, which caused fires in the area of ​​millions of square kilometers in Siberia today, as if burning from one end of the horizon. To the other end. The earth’s crust was torn apart, and lava gushed out like a torrent, surging almost an entire continent. Volcanic eruptions did not subside until millions of years later. During this period, there were volcanic eruptions one after another, a longer pause, and then a series of violent eruptions. Volcanoes emit unimaginable amounts of volcanic material, including lava, gas, and dust. Some people believe that large-scale volcanic eruptions are the “super killers” of the Permian. First of all, the volcanic eruption sent at least tens of thousands of tons of dust into the atmosphere, the sun was blocked, and the global temperature dropped as a result, and this was only the beginning. Then, as the clouds open and sunrise, the super large amount of gas (containing a large amount of carbon dioxide) volatilized by the lava envelops the earth like cotton wool, and is “wrapped” for thousands of years. Carbon dioxide is a typical greenhouse gas, and it must have appeared at that time. Global warming. In other words, the earth at that time suffered a double blow: first a period of severe cold, and then a long period of heat. Such a severe climate change will inevitably lead to mass extinction. Of course, this extinction process is a long one, possibly as long as 1 million years.
  However, some people believe that the Siberian volcanic eruption is indeed deadly, but it will not wipe out 90% of the world’s living things. There must be more terrible catastrophic events behind the extinction of species in the Permian. As a result, another scientist told a “full story” of the Permian extinction: First, the Siberian volcano erupted, and a large amount of lava rushed out from the depths of the earth’s crust. This is the first “killer”. Then came a cold winter, followed by a slow but persistent temperature rise, and finally the global temperature rose by 4 to 5 degrees Celsius. Some species on the land could not bear the heat and gradually became extinct. Later, the ocean temperature also rose, and a large number of marine life died. After that, the second “killer”-the methane dry ice on the seabed was “rebounded” due to the warming of sea water. A large amount of greenhouse gases entered the atmosphere, and the global temperature rose by 5 degrees Celsius, so that the temperature was 10 degrees Celsius higher than before. , It sounds not much, but it is enough to turn an oasis into a desert.
  The Permian mass extinction event led to the extinction of 90% of the earth’s species, but it also gave the earth’s ecosystem a complete renewal, paving the way for the evolution of reptiles such as dinosaurs.