Now the Hunters must be the Hunted (Xenomorph facts)

The Xenomorph

Spicies:

Carrier Xenomorph,Drone Xenomorph,Bodyburster,Wild Boar Alien,Arachnid Alien,Arachnoid,Facehugger,Deacon (Prometheus),Empress,Flying Alien,Flying Queen,Gorilla Alien,Hive Warrior,Jock-Alien,K-Series,Killer Crab Alien,King Alien,Leech Alien,Mantis Alien,Newborn Xenomorph,Night Cougar Alien,Panther Alien,Predalien,Predqueen,Razor Claws,Rhino Alien,Red Alien,Runner,Scorpion Alien,Smasher,Snake Alien,Super-Evolution Alien,Swarm Alien,Swimmer,Warrior Xenomorph and Spitter Xenomorph. ;D

Infomation:
There are no solid facts as to the origins of the Xenomorph species; instead, there are many assumptions which can neither be confirmed nor denied. Based on the limited information we have, the most commonly accepted hypothesis is that they are an artificially created species, although another hypothesis says that they evolved naturally on a planet much different than our own.

The Xenomorph could be the result of genetic manipulation by Mala'kak (also known as the "Engineers" or "Space Jockeys") as a terraforming mechanism about ten million years ago, but apparently it went horribly wrong. (This theory has been twisted slightly by Prometheus, as they created an artificial subspecies, the "Deacon" or proto-alien. (Deacon (Prometheus))

Another theory is that they were actually the oldest and most technologically advanced of all races, but a sort of plague wiped out all the adults, leaving the offspring to devolve into a bestial state. The Mala'kak (Space Jockeys) may have been a close ally, possibly explaining why Xenomorph eggs were on their ships to LV-223 and LV-426 (transportation away from the plague).

Other ideas include that they were created by another race, perhaps the Yautja (Predator) as an "ultimate prey". Xenomorphs are specifically said to not be indigenous to LV-426, a relatively small and unknown planet, where a large body of their eggs were found in the hold of a derelict Mala'ka/Space Jockey ship. No one knows if they were using the eggs as research or as a bio-weapon. Some say that billions of years ago, the advanced race (probably the "Space Jockeys") controlled much of the universe with the Xenomorphs, but were wiped out by them.


The Infomation[aliens.wikia.com]
Life Cycle
Spicies (Abit Rushed and not compleatly correct)