Humans are the most widespread creatures on Earth in the present, due to their superior intelligence. They are also the only animals to voluntarily clothe themselves. Their success is partly down to the fact that they adapt their environment to suit them, rather than vice versa.
Humanity's origins are in primitive primates, which gradually evolved into taller and more intelligent creatures, such as Australopithecus, in the Pliocene epoch. (Episode 3.10) Later on in the Pliocene epoch, the Australopithecus evolved into the Homo genus, with Homo Sapiens (humans) first appearing in the Pleistocene. Eventually, every other Homo species died out, but humanity survived due to their migration and adaptation. (Episode 2.5)
In recent millenia, as the centuries went by, humanity advanced faster than ever before; with scientific breakthroughs and new technologies arising during the Medieval ages and beyond. (Episode 3.7) Some of humanity's mythologies were also influenced by creatures which came through Anomalies into this period of their history. (Shadow of the Jaguar, Episode 3.1, Sisiutl)
In the early 21st Century, small teams and groups of humans began to discover the existence of the Anomalies. As a result, teams and organisations of these humans (such as the Anomaly branch of the Home Office, the Anomaly Research Centre, the Cross Photonics' Special Projects Group, and the rebooted Project Magnet) were formed to predict and contain the Anomalies, and to combat the threat posed by creatures which came through them.
Humanity's future fate appears to change with the future, although it is often grim. Helen Cutter once speculated that humanity probably met its extinction by becoming the prey of a more successful species (such as the Future Predator). (Episode 1.6) Nick Cutter at one point speculated that humanity would probably evolve into the Mer Creatures. (Episode 2.4)
It is known that in one possibble future, at some point in the near future, humanity apparently created Future Predators, which turned on them and apparently hunted them to extinction. (Series 3 Episode 3.3, 3.9, 3.10)
In an alternate future in which the Earth was sterile and dying due to New Dawn's effects on the planet, humanity built underground bunkers as shelters from the inhospitable conditions; the surviving humans became nomads, moving from bunker to bunker. It is believed that due to lack of resources and water supplies becoming poisoned, humanity eventually died out. (Episode 4.7 5.6)