Part 1 Printing the Circuit Board. 1. Choose a method to use for creating the PCB. Your choice will usually be based on the availability of materials needed by the method, the technical difficulty level of the method or the quality of PCB you desire to obtain.
Permian-Triassic Extinction. In this video segment from Evolution: Extinction!, geologist Peter Ward shows rock layers laid down during the Permian and Triassic periods. The Permian layers contain abundant animal fossils and fossilized traces of animals, while the Triassic layers are almost devoid of fossils, suggesting a mass extinction event occurred 250 million years ago, at the end of the Permian.
This was what happened during the first mass extinction of animal life on the Earth, 440 million years ago. (Photo: Colourbox). With its warm climate and plenty of food, the Earth was a good place to live for the many animals with shells, legs and teeth. Animal life had just conquered the oceans 440 million years ago.