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Early modern period – The chronological limits of this period are open to debate. It emerges from the Late Middle Ages (c. 1500), demarcated by historians as beginning with the fall of Constantinople in 1453, in forms such as the Italian Renaissance in the West, the Ming dynasty in the East, and the rise of the Aztecs in the New World.
The Paleo-Indian (less frequently, Lithic) period or era is that which spans from the first signs of human presence in the region, which many believe to have happened due to the Bering Land Bridge, to the establishment of agriculture and other practices (e.g. pottery, permanent settlements) and subsistence techniques characteristic of proto-civilizations. [2]
At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction, [9] often comprising an accumulation of smaller extinction events over a relatively brief period. [10] The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes.
The Paleolithic or Palaeolithic (c. 3.3 million – c. 11,700 years ago) (/ ˌ p eɪ l i oʊ ˈ l ɪ θ ɪ k, ˌ p æ l i-/ PAY-lee-oh-LITH-ik, PAL-ee-), also called the Old Stone Age (from Ancient Greek παλαιός (palaiós) 'old' and λίθος (líthos) 'stone'), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost ...
A period is equivalent to a chronostratigraphic system. [14] [13] There are 22 defined periods, with the current being the Quaternary period. [2] As an exception, two subperiods are used for the Carboniferous Period. [14] An epoch is the second smallest geochronologic unit. It is equivalent to a chronostratigraphic series.
Diagram illustrating how the uterus lining builds up and breaks down during the menstrual cycle Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone ...
A quadrennium (plural: quadrennia or quadrenniums) is also a period of four years, most commonly used in reference to the four-year period between each Olympic Games. [8] It is also used in reference to the four-year interval between leap years, for example when wishing friends and family a "happy quadrennium" on February 29. [citation needed ...
The modern era or the modern period is considered the current historical period of human history. It was originally applied to the history of Europe and Western history for events that came after the Middle Ages , often from around the year 1500, like the Reformation in Germany giving rise to Protestantism .