history of the Earth

 About 6 mln years ago Mediterranean Sea almost completely dissapperd as it was slowly cutting off from the global ocean, the last one was cut off through what is now the Strait of Gibraltar, which did not exist then, but the process itself began 15 million years ago. At the peak of the crisis, the water level was so low that the sea had shrunk to a few large, hypersaline lagoons. At this time Nile was reaching Sicily and was connecting with the Danube. For the many animals, plants and microorganisms it was a death sentence but for some land animals of the area, this was an opportunity to explore new territories. After 600,000 years of desiccations, river erosion near Gibraltar caused the Zanclean megaflood which brought bach the sea and ended the crisis. As the collision between Africa and Eurasia continues, it is highly likely that the Strait of Gibraltar will close again but this time water probably won't evaporated so fast becouse we live in colder climat. sor...

Named for the Ediacara Hills of South Australia, in which they were discovered in 1946, were the first animals, despite sponges, made up of more than one type of cell, that required atmospheric oxygen for their growth. Almost all of these fossils are dated between 575 and 542 million years ago. These creatures had wide variety of shapes and sizes from circular discs reaching 20 cm to frond-shaped that can be as long as 1 meter. Some of them were similar to today's jellyfishes, soft corals and seeweed but some were unlike to the organisms known today. At the begining of the Cambrian explosion they disappear almost simultaneously probably becouse of the emergence of Cambrian predator animals. Ediacaran fauna's relationships with the rest of extant and extinct animals has not been possible to firmly establish, so they may not be connected to the rest of the organisms on Earth. sources:  https://www.google.com/search?q=ediakar&tbm=isch&hl=pl&bih=839&biw=1...

In 2018 bones of the perucetus were discovered in Peru and made it probably the heaviest animal to ever exist. This gigantic mammal has massive bones which aren't result of the disease and lived about 40 million years ago. To determine mass scientists used two paterns: one assuming the avarege skeletal fraction of adult manatees which are the living marine mammales with the strongest bone mass increase and the minimum skeletal volume mass and second using the living whale's lowest skeletal fraction and the maximum skeleton volume. From these two estimates, it could have weighed from 85 to 340 tons, to compare biggest whale weights 190 tons. Still we don't have the rest of the skeleton so we can only assuming perucetus' mass. Probably this thick bones were helping the animal control it,s buoyancy like with living manatees and dugongs. It mean that perucetus was living in the shallower parts of the ocean than most whales today. Massive bones could have restricted movement...