The chronology of Homo sapiens

At Jebel Irhoud, in Morocco, fossils about 315,000 years old are the oldest attributed to the Homo sapiens lineage.

All living humans inherit their mitochondrial DNA from one woman who lived in Africa about 200,000 years ago, one ancestor among many.

Between about 70,000 and 50,000 years ago, the Homo sapiens populations from which almost all non-Africans descend spread out of Africa.

Sands from a rock shelter in northern Australia date the first Australians to about 65,000 years ago, an age still disputed.

A painted hunting scene in a cave of Sulawesi, Indonesia, is at least 51,200 years old, the oldest known cave painting.

Between about 50,500 and 43,500 years ago, Homo sapiens and Neanderthals interbred, leaving two to three per cent of Neanderthal DNA in all non-Africans.

The Neanderthals disappeared from Europe about 40,000 years ago, region by region, after several millennia alongside Homo sapiens.

Human footprints in New Mexico, dated to 23,000 to 21,000 years ago, put people in the Americas at the height of the last glaciation.

In the Fertile Crescent, about 11,500 years ago, people began sowing wild cereals and penning wild goats and sheep: farming had begun.

Uruk, in southern Iraq, is the settlement conventionally called the first city, and it gave its name to the centuries around 3500 BCE in which cities and the state took shape.

The wheel and the wheeled vehicle appear almost simultaneously about 5,400 years ago, in several regions of Eurasia, five millennia after the beginnings of farming.

The oldest known writing, proto-cuneiform, appeared about 5,200 years ago in the temple precinct of Uruk, to record rations, livestock and deliveries.

The Yamnaya, mobile herders of the steppes north of the Black Sea, spread with their wagons and herds from about 5,000 years ago.

From about 4,400 years ago, farming peoples spread from the borderlands of Nigeria and Cameroon through the equatorial forest and beyond, carrying the Bantu languages.

The Black Death, which reached the Mediterranean in 1346 and killed perhaps half of Europe's people by 1353, has been traced by ancient DNA to a source near Lake Issyk-Kul, in present-day Kyrgyzstan.

Around 1450, at Mainz, Johannes Gutenberg's press with movable metal type turned the book, until then copied by hand over months, into a manufactured object.

From 1492, plants, animals and diseases crossed the Atlantic in both directions: maize and potato eastward, wheat, horses, cattle and above all pathogens westward.

In 1854, John Snow's investigation of a cholera outbreak in Soho, London, established that the disease travelled by water and not by air.

On 24 November 1859, Charles Darwin published On the Origin of Species, replacing a fixed world of species with a genealogy of the living shaped by natural selection.

On 24 March 1882, Robert Koch announced the discovery of the tuberculosis bacillus, and within a generation living microbes replaced miasmas as the explanation of infectious disease.

Edison's Pearl Street station, switched on in Manhattan in September 1882, was the first central power network, supplying current to a whole district as a service.

The Haber-Bosch process, from 1908, makes ammonia from the nitrogen of the air, which plants cannot use on their own, and about half the nitrogen in a human body today comes from it.

In August 1928, Alexander Fleming noticed that a mould contaminating a culture dish had cleared the staphylococci around it, and identified penicillin.

The first nuclear test, Trinity, took place on 16 July 1945 in New Mexico, and the atmospheric tests that followed spread artificial radionuclides across the planet.

The transistor was demonstrated on 23 December 1947 at Bell Labs, a sliver of germanium under two gold contacts amplifying a signal without vacuum or heated filament.

On 25 April 1953, James Watson and Francis Crick proposed the double helix of DNA, alongside the X-ray work of Rosalind Franklin and Maurice Wilkins at King's College London.

Since 1958, Charles David Keeling's measurements at Mauna Loa, in Hawaii, have recorded the rise of carbon dioxide in the atmosphere, from 315 to about 430 parts per million.

From the mid-1960s, semi-dwarf wheat and rice varieties, grown with fertiliser and irrigation, raised harvests, and by the 1990s they covered three quarters of Asia's rice fields.

On 8 May 1980, the World Health Assembly declared smallpox eradicated, two and a half years after the last natural case, diagnosed in Somalia in 1977.

HIV-1 passed from chimpanzees to humans in central Africa at the beginning of the twentieth century, decades before the syndrome it causes was recognised in 1981.

The World Wide Web, devised at CERN by Tim Berners-Lee and announced publicly in 1991, is a system of documents with universal addresses, linked to one another.

The Human Genome Project published a first draft of the human sequence, three billion base pairs, in 2001 and the finished sequence in 2004, with a public consortium and a private company racing side by side.

The first Neanderthal genome, read in 2010 from bones found in Croatia, showed that people outside Africa carry Neanderthal DNA and sub-Saharan Africans do not.

CRISPR, a defence system of bacteria against viruses, was shown in 2012 to be programmable at will, and became a tool that cuts DNA at a chosen place.

Deep learning, the training of many-layered neural networks on large masses of data, imposed itself in the early 2010s, notably at the ImageNet competition of 2012.