Arthropods (about 570 MYA)
![Picture](/uploads/2/5/8/6/25868552/495593607.jpg)
-invertebrate animal exoskeleton
-Insects, Spiders etc.
-bilateral symmetry (both sides of the body are the same)
-jointed legs and appendages
-body divided into distinct parts
-Insects, Spiders etc.
-bilateral symmetry (both sides of the body are the same)
-jointed legs and appendages
-body divided into distinct parts
First Mass Extinction (about 544 MYA)
![Picture](/uploads/2/5/8/6/25868552/49780.jpg)
Throughout Earth's history, there have been periods where climate changed dramatically. The response was mass extinction events, when many species went extinct followed by a very slow recovery. The first great mass extinction event took place at the end of the Ordovician, when according to the fossil record, 60% of all genera of both terrestrial and marine life worldwide were exterminated.