The Origins of Mankind

Life in a Stoneage (Upper Paleolithic) European village, 40,000 years ago

This page lists events in the early prehistory of the universe and the Earth, up to approximately 10,000 BC. Note that many of these dates are speculative or very rough estimates. For events from 10,000 BC onwards, see 10th millennium BC. For greater detail see the articles on the various geological periods.

And God created the Heaven and the Earth...

• 13.7 ± 0.2 billion years ago: Beginning of the Universe (the Big Bang).
• 13.2 billion years ago: Existence of the first known star-forming galaxies.
• 4.6 billion years ago: The solar system begins to form.
• 4.5 billion years ago: Formation of the Earth (see Age of the Earth).

The beginning of life

• 3.9 to 4.1 billion years ago: Origin of life (cyanobacteria).
• 2.3 billion years ago: First known Snowball Earth ice age (the entire Earth covered with ice; thus the name).
• 1.8 to 2.1 billion years ago: Appearance of the earliest Eukaryotes (type of cells making up plants and one-celled organisms, but not animals).
• 750 million years ago: Beginning of a possible Snowball Earth ice age.
• 600 million years ago: First complex multicelled lifeforms (Prokaryotes).
• 580 million years ago: End of possible Snowball Earth ice age.
• 575 million years ago: Origin of the oldest animal fossils.
• 540 million years ago: End of the Precambrian period and beginning of the Cambrian. Time of the Cambrian explosion and appearance of the first Vertebrates.
• 500 million years ago: Ordovician period begins.
• 435 million years ago: Silurian period begins.
• 420 million years ago: First creatures with lungs.
• 400 million years ago: Devonian period begins.
• 340 million years ago: Carboniferous period begins.
• 280 million years ago: Permian period begins.
• 251.4 million years ago: the Permian mass extinction. Palaeozoic era ends. Beginning of the Triassic period, the Mesozoic era and of the emergence of the dinosaurs.
• 195 million years ago: Jurassic period begins; appearance of the earliest mammals.
• 135 million years ago: Cretaceous period begins.
• 65 million years ago: Cretaceous-Tertiary extinction event at the end of the Cretaceous period (end of the Mesozoic era); start of the Tertiary period (Cenozoic era). End of the age of the dinosaurs. Scientists theorize that the K-T extinctions were caused by one or more catastrophic events, such as massive asteroid impacts or volcanic activity.
• 60 million years ago: First primates begin to evolve.
• 49 million years ago: Whales (up until then, land animals) return to the water.
• 40 million years ago: Age of the Catarrhini parvorder; first canines evolve. Man's best friend here long before Man.
• 36 million years ago: End of Eocene, start of Oligocene epoch.
• 34 million years ago:Cats begin to evolve.
• 26 million years ago: Emergence of the first true elephants.
• 24 million years ago: Miocene epoch begins.
• 20 million years ago: First forms of grass appear.
• 18-12 million years ago: Emergence of the Hominidae family. (Apes and ancestors of Man).
• 5-7 million years ago: Pan/Homo split. Closely related, Man and Chimpanzee part ways.
• 5.5 million years ago: Appearance of the genus Ardipithecus.
• 5 million years ago: Pliocene epoch begins.
• 4.5 million years ago: Appearance of the genus Australopithecus, maybe ancestor to the genus Homo.
• 4 million years ago: Start of last ice age.

Neanderthals, our earliest cousins, roamed the Earth 30,000 to 250,000 years ago

Meet the Ancestors

Writers have been around for 30,000 years

Volcanic explosion 71,000 years ago reduced the world human population to a possible 2,000 souls
According to the Toba catastrophe theory, the consequences of a massive volcanic eruption drove the world's human population to the brink of extinction between 70,000–75,000 years ago when the Toba caldera in Indonesia underwent an eruption of category 8 (or "mega-colossal") on the Volcanic Explosivity Index, releasing between 2500 and 3000 km3 of dense rock equivalent.
Genetic evidence suggests that all humans alive today, despite apparent variety, are descended from a very small population, perhaps between 1,000 to 10,000 breeding pairs about 70,000 years ago.

The Cambrian explosion or Cambrian radiation, the Permian mass extinction and the K-T extinction The Cambrian explosion or Cambrian radiation was the relatively rapid appearance, over a period of many million years, of most major groups of complex animals around 530 million years ago, as found in the fossil record. This was accompanied by a major diversification of other organisms, including animals, phytoplankton, and calcimicrobes. Before about 580 million years ago, most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 or 80 million years the rate of evolution accelerated by an order of magnitude (as defined in terms of the extinction and origination rate of species) and the diversity of life began to resemble today’s.

... all caused by violent volcanic eruptions? The Cambrian explosion has generated extensive scientific debate. The seemingly rapid appearance of fossils in the “Primordial Strata” was noted as early as the mid 19th century, and Charles Darwin saw it as one of the main objections that could be made against his theory of evolution by natural selection. The long-running puzzlement about the appearance of the Cambrian fauna, seemingly abruptly and from nowhere, centers on three key points: whether there really was a mass diversification of complex organisms over a relatively short period of time during the early Cambrian; what might have caused such rapid change; and what it would imply about the origin and evolution of animals. Interpretation is difficult due to a limited supply of evidence, based mainly on an incomplete fossil record and chemical signatures left in Cambrian rocks.   The super-continent of Permia, 250 million years ago The Permian Mass Extinction which ocurred 250 million years ago, wiped out 95% of the existing species, and began the age of the Dinosaurs. The mass extinction event at the end of the Permian period -- where more than two-thirds of reptile and amphibian families perished and 95% of oceans life forms became extinct -- was probably caused by poisonous volcanic gas, according to research published in the journal Geology. The researchers believe that volcanic gases from the eruption, near present day Siberia, depleted earth's protective ozone layer and acidified the land and sea.