BIO 1130 Lecture Notes - Lecture 17: French Revolution, Cyanobacteria, Leading Edge

• School: University of Ottawa
• Department: Biology
• Course: BIO 1130
• Professor: Jon Houseman

Document Summary

Explosion of multicellular life from oceans to land and a massive extinction. I"m in the process of updating these pages. The traditional line on the geological time scale for the appearance of multicellular animals is the start of the cambrian period 542 million years ago. As you will see shortly, this may not be the actual date when the first animals appear in the ancient oceans of the planet. Before we get to that, let"s take a look at why biologists consider this to be an explosive period for animal evolution. Part of the reason for the explosion is because fossils appear in large numbers for the first time ever and in they"re in the. Fossils are best made from animals that have minerals incorporated into their bodies, most often as a skeleton. There are so many cambrian fossils with shells that biologists and geologists often refer to the time as the appearance of the shelly animals.