All of the major animal groups of the Ordovician oceans survived, including trilobites, "When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Silurian system was deposited, they seem to me to become ennobled.Judging from the past we may safely infer that not one living species will transmit its unaltered likeness to distant futurity." (Charles Darwin) From primal swamp to speaking humans: Ernst Haeckel said (1903) that the Pithecoiden (monkey) theory of human evolution requires tracing our animal ancestors before monkeys.Galena can contain minor amounts of antimony, arsenic, bismuth, cadmium, copper, silver, and zinc See and stalagmites.Encountering impermeable strata (such as toadstone) it forms underground lakes in the limestone which overflow to the surface as natural springs (a resurgence).It is suggested that analysis of sedimentary pyrite from the Belingwe sedimentary basin in Zimbabwe may provide evidence for bacterial reduction at this date.2,500,000,000 to 542,000,000 years ago The Proterozoic Eon: the most recent part of the Precambrian Supereon.All plants were responsible for the transformation, but Archaeopteris was important because it made up 90 percent of the forests during the last 15 million years when these changes accelerated" ...
Mesoproterozoic from 1,600,000,000 to 1,000,000,000 years ago. Particular importance attaches to occurred around 1,300,000,000 years ago during the late Mesoproterzoic era, after the earth's transition to a more highly oxygenated atmosphere with an ozone screen. Deposits that made Westmorland Green slate formed around 450 million years ago. About 50 million years later, the material was altered by heat and pressure (metamorphosed) to slate, during mountain-building. After many more millions of years, they resembled patches of moss a few centimeters high.
The end-Frasnian extinction was most pronounced in tropical environments, particularly in the reefs of the shallow seas.
Reef building sponges called stromatoporoids and corals suffered losses and stromatoporoids finally disappeared in the third extinction near the end of the Devonian.
4,540,000,000 (4.54 billion) years ago Formation of planet Earth - Usher's date was ).
Archeozoic: end of Azoic to 2,500,000,000 years ago: The era of the earliest living beings on earth.