Scientists agree that a large number of living species may become extinct in a short time
In 1982, American paleontologists Jack Sepkoski (1948-1999) and David M. Raup ( 1933-2015) from the University of Chicago in the US state of Illinois reviewed the largest extinctions of living species on Earth. They called this review “The Big Five” because they determined that there were 5 such unpleasant events in the world. In the past 500 years, the Blue Planet has witnessed intense periods in which more than half of living things have disappeared. More than 90% of the species that once crawled, walked, flew or swam on Earth have become extinct.
- The first great extinction of living beings was 445 million years ago. Between 60 % and 70% of living creatures disappeared then. Experts say that this extinction happened due to a short but strong ice age. The living world of that time was mostly in the oceans. Scientists believe that the rapid formation of glaciers froze most of the water on Earth and caused a drastic drop in sea levels. Marine organisms (sponges and algae) and shellfish, cephalopods and some fish species suffered the most.
- The second great extinction on Earth was 360 to 375 million years ago. Then the living beings disappeared. And then the sea creatures suffered the most. The reason is the decrease in the amount of oxygen in the oceans.
- The third great extinction on Earth was particularly devastating. The Permian-Triassic extinction occurred approximately 252 million years ago. This period is called the “mother of all extinctions” because about 96% of living organisms have disappeared. Experts agree that the third extinction occurred due to an asteroid impact and strong volcanic eruptive activity. Then the suffering hit both the sea and the land. There are various theories about the duration of this extinction. Estimates range from a few million to 200,000 years. Interestingly, insects and some reptiles disappeared in the mass extinction at that time.
- The fourth mass extinction took away 70 to 80% of the species of living beings for many but few obscure reasons. One theory holds that the fourth extinction occurred due to a strong lava eruption followed by the release of large amounts of carbon dioxide. This has led to rapid climate change. Some scientists believe that an asteroid impact occurred, although no crater has been found so far. At the transition from the Triassic to the Jurassic period, numerous species of large terrestrial animals disappeared, including the largest number of archosaurs (ancestor of dinosaurs), but also crocodiles and today’s birds.
- The fifth and last great extinction so far occurred 66 million years ago (at the end of the Cretaceous). Experts say the cause was again an asteroid strike in the Mexican area of today’s Yucatan Peninsula. Established scientific theories are evidenced by a huge crater formed in the area. All non-flying dinosaurs are extinct. A large number of mammals (turtles, frogs, crocodiles and birds) survived on land. Sharks, starfish and hedgehogs survived in the seas. The disappearance of dinosaurs allowed the spread of mammals, which eventually caused the appearance of Homo sapiens / humans. Yet man is responsible for the new mass extinction we are increasingly facing today.
- Potentially 6 species extinction. Albert Einstein stated that “the disappearance of bees will cause the disappearance of life on Earth because man will then have about 4 years of life left.” Without bees there is no pollination and without pollination there is no fruit (food) so ultimately there are no people. That is why everything should be done because of the frequent news and the death of bees that we hear every day and other harmful human influences on nature. This year, the main slogan of Earth Day was “Investing in our planet”. The focus was on 3 guidelines, act boldly, innovate widely and realize justly with which every person can get involved and save the Earth with small but significant steps. So during the walk you can collect the scattered waste and dispose of it and the planned places for waste. Use a canvas shopping bag (or other reusable bag) when shopping instead of plastic bags. Choose glass or paper packaging instead of plastic packaging. Include more local stores and businesses in your shopping list. A lot can be done in your own home. Choose environmentally friendly cleaners (baking soda, lemon, vinegar, essential oils, etc.) instead of aggressive and chemical cleaners. With better control of the device, great energy savings can be achieved. Turn off the devices when you are not actively using any of the devices.
Click to access raup-david.pdf
https://www.jstor.org/stable/4331943
https://en.wikipedia.org/wiki/Jack_Sepkoski
magicandbeauty 