How long people have been on earth

Power and energy : 1 watt of power uses 1 joule of energy per second; about watts in 1 horsepower; 3, kilojoules kJ or kilocalories kcal in 1 kWh of energy, sustaining 1, watts for 1 hour.

For example , a watt incandescent light bulb illuminates a room; 80 watts sustain human basal metabolic rate, using 6, kJ or 1, kcal or 1. Patrick Doncaster , 7 November , one of the then 7,,, rising by per minute, 79 million per year. Evolution of life on Earth 4,,, earliest life on Earth: single-celled prokaryotic Archaea Hadean Eon , 3.

Human evolution 2,, earliest human, Homo sp. Years ago. There are currently seven billion people alive today and the Population Reference Bureau estimates that about billion people have ever lived. This means that we are nowhere near close to having more alive than dead.

In fact, there are 15 dead people for every person living. We surpassed seven billion dead way back between BC and AD1. Fans of science fiction may be reaching for their copies of Arthur C Clarke's classic, A Space Odyssey, at this point.

In that book, he makes the assertion: "Behind every man now alive stand 30 ghosts, for that is the ratio by which the dead outnumber the living. There were maybe 3.

And will we ever reach a point where there are more alive than dead? The structure and anatomy of early humans are much different than humans now. Currently, we humans are much lighter than our ancestors. We have large brains with a skull that has high and thin walls. We have thinner jaws and smaller teeth. Our ancestors millions did not have these features, but the features we see now slowly evolved as time passed.

The group of hominids shown here includes many of our direct ancestors and evolutionary cousins. About 1. This human ancestor not only walked fully upright, but had much larger brains than Homo habilis: nearly twice as large, on average. Homo erectus became the first direct human ancestor to leave Africa, and the first to display evidence of using fire. Homo habilis was likely driven to extinction more than a million years ago, as was the last Australopithecus.

Across the world, new examples of the genus Homo emerged, including Homo antecessor in Europe which may be an evolved habilis or erectus, or an early form of heidelbergensis about 1. Approximately , years ago, the earliest evidence for cooking appears; about , years ago, the first evidence for clothing appears.

The oldest fossil remnants of Homo sapiens now date back to ,, years ago, and were This find, dating back to only , pushes back our species' origin earlier than the development of the Neanderthals, and suggest that we didn't evolve only in East Africa, as previously believed.

Approximately , years ago, the first Homo sapiens — anatomically modern humans — arose alongside our other hominid relatives. It is unknown whether we descended directly from Homo erectus, heidelbergensis, or antecessor, although Neanderthals, which came slightly later at , years ago, most certainly came from Homo heidelbergensis.

Modern speech is thought to have arisen almost as soon as Homo sapiens did. It took Yet, in that short time, we've managed to figure out the entire cosmic story that led to our existence. Fortunately, the story won't end with us, as it's still being written.

Evolutionarily speaking, human beings - or homo sapiens - have been around for a cosmic Based on how evolution works, it is unlikely there will be any humans left even just a few million years from now. This is a BETA experience.

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