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The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared.
539 Ma – present. The Phanerozoic Eon (Greek: period of well-displayed life) marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. It is subdivided into three eras, the Paleozoic, Mesozoic and Cenozoic, with major mass extinctions at division points.
Cambrian. g. g. FAD of the Conodont Iapetognathus fluctivagus. The Cambrian ( / ˈkæmbri.ən, ˈkeɪm -/ KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. [5] The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of ...
The Devonian (/ dəˈvoʊni.ən, dɛ -/ də-VOH-nee-ən, deh-) [9][10] is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.2 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.9 Ma.
The Cambrian explosion (also known as Cambrian radiation [1] or Cambrian diversification) is an interval of time approximately in the Cambrian period of the early Paleozoic when a sudden radiation of complex life occurred, and practically all major animal phyla started appearing in the fossil record.
Vertical axis scale: millions of years ago. The Ordovician (/ ɔːrdəˈvɪʃi.ən, - doʊ -, - ˈvɪʃən / or-də-VISH-ee-ən, -doh-, -VISH-ən) [9] is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. [2] The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing ...