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The history of paleontology traces the history of the effort to understand the history of life on Earth by studying the fossil record left behind by living organisms. Since it is concerned with understanding living organisms of the past, paleontology can be considered to be a field of biology, but its historical development has been closely tied to geology and the effort to understand the ...
Basilosaurus, one of the first of the giant whales, appeared in the fossil record. 38 Ma Earliest bears. 37 Ma First nimravid ("false saber-toothed cats") carnivores — these species are unrelated to modern-type felines. First alligators and ruminants. 35 Ma Grasses diversify from among the monocot angiosperms; grasslands begin to expand.
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 direct known life on Earth are stromatolite fossils which have been found in 3.480-billion-year-old ... Some computer models suggest life began as early ...
Quetzalcoatlus, one of the largest flying animals to ever live, first appears in the fossil record. c. 66.038 ± 0.011 Ma – Cretaceous-Paleogene extinction event at the end of the Cretaceous Period marks the end of the Mesozoic era and the age of the dinosaurs; start of the Paleogene Period and the current Cenozoic era.
Fossils of organisms' bodies are usually the most informative type of evidence. The most common types are wood, bones, and shells. [57] Fossilisation is a rare event, and most fossils are destroyed by erosion or metamorphism before they can be observed. Hence the fossil record is very incomplete, increasingly so further back in time.
Fossils attributed to H. sapiens, along with stone tools, dated to approximately 300,000 years ago, found at Jebel Irhoud, Morocco [51] yield the earliest fossil evidence for anatomically modern Homo sapiens. Modern human presence in East Africa , at 276 kya. [52]
The earliest trilobite fossils are about 530 million years old, but the class was already quite diverse and cosmopolitan, suggesting they had been around for quite some time. [82] The fossil record of trilobites began with the appearance of trilobites with mineral exoskeletons—not from the time of their origin.