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Bones of the first gill arch became the upper and lower jaw, while those from the second arch became the hyomandibula, ceratohyal and basihyal; this closed two of the seven pairs of gills. The gap between the first and second arches just below the braincase (fused with upper jaw) created a pair of spiracles , which opened in the skin and led to ...
This is a list of dates associated with the prehistoric peopling of the world (first known presence of Homo sapiens). The list is divided into four categories, Middle Paleolithic (before 50,000 years ago), Upper Paleolithic (50,000 to 12,500 years ago), Holocene (12,500 to 500 years ago) and Modern ( Age of Sail and modern exploration).
The first known footprints on land date to 530 Ma. [74] 520 Ma Earliest graptolites. [75] 511 Ma Earliest crustaceans. [76] 505 Ma Fossilization of the Burgess Shale: 500 Ma Jellyfish have existed since at least this time. 485 Ma First vertebrates with true bones (jawless fishes). 450 Ma First complete conodonts and echinoids appear. 440 Ma
The Bantu expansion has spread the Bantu languages to Central, Eastern and Southern Africa, partly replacing the indigenous populations of these regions, including the African Pygmies, Hadza people and San people. Beginning about 3,000 years ago, it reached South Africa about 1,700 years ago.
Metalworking was first used in the creation of copper tools and ornaments around 6400 BCE. [48] Gold and silver soon followed, primarily for use in ornaments. [48] The first signs of bronze, an alloy of copper and tin, date to around 4500 BCE, [62] but the alloy did not become widely used until the 3rd millennium BCE. [63]
The first debates about the nature of human evolution arose between Thomas Henry Huxley and Richard Owen. Huxley argued for human evolution from apes by illustrating many of the similarities and differences between humans and other apes, and did so particularly in his 1863 book Evidence as to Man's Place in Nature .
The first footprints were found in a dry lake bed in White Sands National Park in 2009. Scientists at the U.S. Geological Survey recently analyzed seeds stuck in the footprints to determine their ...
45 kya – 43 kya: The first waves of Homo sapiens arrive in Europe, comprising the Early European modern humans. [34] [35] 45 kya – 40 kya: Châtelperronian cultures in France. [36] 42 kya: Time frame of the Laschamp event, the first geomagnetic excursion studied and one of the few full global magnetic field reversals known.