At some point far back in time, a common ancestor gave rise to two main groups of life: bacteria and archaea. A timeline can provide additional information about life's history not visible on an evolutionary tree. These include major geologic events, climate changes, radiations of organisms into new habitats, changes in ecosystems, changes … Important events in the history of life (text-only version) View the Graphical timeline. Read this ScienceStruck article to gain more information about this era on Earth, along with the respective major geological events and related facts. All species of mammals are capable of milk production. All are very demanding and rewarding industries. The principals and employees of Evolutionary Events have worked for many years on creating sales and marketing events and incentive travel programs within the Hi-Tech, Medical, Insurance, Financial and Entertainment markets. The Paleozoic Era is one of the most important geological divisions of our planet's geochronological timescale, as it marks the extensive evolution of life, along with the largest mass extinction. Important Events in the History of Life A timeline can provide additional information about life's history not visible on an evolutionary tree. The Ordovician period, from 485 to 444 million years ago, was a time of dramatic changes for life on Earth. EVOLUTIONARY EVENTS . The Geologic Time Scale is the history of the Earth broken down into four spans of time marked by various events, such as the emergence of certain species, their evolution, and their extinction, that help distinguish one era from another. The last major evolutionary change that we will look at was the ability to produce milk.