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Although the claim is controversial, carbon contained in rocks in Greenland suggested potential evidence of life. 3.7 billion years ago
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Archaea is a domain that made a very early appearance in fossil record. Researchers in Tokyo extracted biologically produced methane from 3.5 billion years old in rocks in Australia.
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Stromatolites (which are layered mats formed by bacteria mineralization) form when biofilms of microorganisms (cyanobacteria) trap and bind sediments to form layered structures. The oldest stromatolite fossils date back to 3.45 billion years ago, suggesting that the earliest signs of life are microbial.
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Cyanobacteria fossils were found to date back 2.6 billion years ago. We found this to correspond with the first appearance of atmospheric oxygen, because O2 is released by cyanobacteria via photosynthesis.
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Eukarya emerged 1.8 billion years ago-- cells that are 100 times bigger than bacteria! This emergence led to multicellularity, a dramatic transition.
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Since purple sulfur bacteria are the only organisms known to produce okenone (pigment used in photosynthesis), when we found okenane in rocks that are 1.64 billion years old, we are able to suggest that purple sulfur bacteria was also present at that time!
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The oldest recognizable eukaryotic multicellular life is the discovery of fossils of algae that date back to 1.6 billion years ago.
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Red algae fossils were discovered 1.2 billion years ago.
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Green algae fossils were discovered 750 million years ago.
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The oldest fossils of sponges was dated back to 650 million years ago.
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Ediacaran Fauna is the region in Australia in which some of the most diverse forms of early animals were first recognized. This is where we were finding much bigger fossils, with tons of diversity! Some were worm like while some looked like fronds.
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In the Cambrian period, some currently existing lineages were recognizable, however 90% of the species that emerged in this period vanished! One important species to note was the emergence of the Phylum Chordata. In this period, chordata began to diversify.
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A rich community of marine animals on shall underwater mud banks. These banks occasionally collapsed, sending these animals to the anoxic bottom where their decomposition was prevented-- in turn allowing us to study their fossils. 505 million years ago-- THRIVING!
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The first invertebrates were able to date back 480 million years ago, probably relatives of insects and spiders. It is still not clear whether they lives on land permanently or not.
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The early terrestrial plants emerged 475 million years ago, resembling mosses and liverworts.
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A bus driver in Scotland found a millipede dating back to 428 million years ago, giving us the oldest fossil of fully terrestrial animal.
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Early insects were found to have emerged 400 million years ago, however the current lineages appear much later.
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Fungi appear 400 million years ago, and we see their association with plants! This new finding was breaking down dead plants, causing diseases, and helping to obtain nutrients.
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The first vertebrates date back 390 million years ago. The fossil was of an animal with an alternating gait, with guesses of that animal being an early tetrapod.
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Familiar forms of life did not emerge until more recently, being about 350 million years ago. Some of these include teleost fish (tuna, salmon, goldfish, walleye, etc.), mammals, birds, and flowering plants.
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Darwin looked into the formation of Weald (a stretch of ridges and valleys in SE England) by erosion. He noticed that this geological formation was over 300 million years old, suggesting that earth must be older
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Dinosaurs first emerged 230 million years ago, and dominated until mass extinction wiped them out 65 million years ago-- birds being the only survivors!
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Mammals evolved from synapsids, and about 150 million years ago, we see our first mammals emerge.
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Birds were descendants of dinosaurs, and the only survivors of their mass extinction! Birds are thought to have emerged from dinosaurs 150 million years ago.
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Flowering plants emerged 130 million years ago.
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Whales, bats, and primates all emerged around 50 million years ago.
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The oldest human fossils are only 200,000 years old! The first fossil was found in Ethiopia.
