Caveman

The very first evolution of humankind. Cavemen are descended from ancient apes. They are typically portrayed as wearing shaggy animal hides, and capable of cave painting, like behaviourally modern humans of the last glacial period. Anachronistically, they are simultaneously shown armed with rocks or cattle bone clubs, unintelligent, and aggressive, traits more like those of archaic humans from hundreds of thousands of years before this period. Most important of all, Cavemen are the only species who can make fire compared to other contemporary animals. Fire appearances help them a lot in cooking food, rituals, agricultures, generating light, smelting, forging. Generally speaking, Cavemen create the first source of energy generation:  Fire.

Fire
An outdoor fire using wood

The ignition and extinguishing of a pile of wood shavings

The fire maps show the locations of actively burning fires around the world on a monthly basis, based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. The colors are based on a count of the number (not size) of fires observed within a 1,000-square-kilometer area. White pixels show the high end of the count—as many as 100 fires in a 1,000-square-kilometer area per day. Yellow pixels show as many as 10 fires, orange shows as many as 5 fires, and red areas as few as 1 fire per day.

Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.[1] Slower oxidative processes like rusting or digestion are not included by this definition.

Fire is hot because the conversion of the weak double bond in molecular oxygen, O2, to the stronger bonds in the combustion products carbon dioxide and water releases energy (418 kJ per 32 g of O2); the bond energies of the fuel play only a minor role here.[2] At a certain point in the combustion reaction, called the ignition point, flames are produced. The flame is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce plasma.[3] Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity will be different.

Fire in its most common form can result in conflagration, which has the potential to cause physical damage through burning. Fire is an important process that affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems.

The negative effects of fire include hazard to life and property, atmospheric pollution, and water contamination.[4] If fire removes protective vegetation, heavy rainfall may lead to an increase in soil erosion by water.[5] Also, when vegetation is burned, the nitrogen it contains is released into the atmosphere, unlike elements such as potassium and phosphorus which remain in the ash and are quickly recycled into the soil. This loss of nitrogen caused by a fire produces a long-term reduction in the fertility of the soil, which only slowly recovers as nitrogen is "fixed" from the atmosphere by lightning and by leguminous plants such as clover.

Fire has been used by humans in rituals, in agriculture for clearing land, for cooking, generating heat and light, for signaling, propulsion purposes, smelting, forging, incineration of waste, cremation, and as a weapon or mode of destruction.