Human

Humans (Latin: Homo sapiens sapiens, meaning Wise Wise Man) are a sentient species within the Genus Homo and part of the primate family. Fossil records date Human existence at about 200,000 years. They are rated as a Tier 3 species on the Forerunner Technological Achievement system, although it is possible they may have adopted a higher Tier 2 during and after the Human-Covenant War by means of weapons research and development.

Throughout their existence, Humans have developed their civilization by engaging in food production on a larger scale, developing language, religious and political philosophies, and exhibiting telescoping technological and infrastructural development. They were studying the stars long before they were able to travel out of their atmosphere. After succeeding in space colonization, the human race was able to terraform and inhabit other planets besides Earth, but the human race is under pressure due to the discovery of the caste-driven Covenant after several centuries of space travel. The total population at the end of the war is unknown.

Prehistory
Homo sapiens sapiens were believed to have appeared in Earth's fossil record between approximately 100,000 and 200,000 years ago (there was another subspecies of Homo sapiens known as Homo sapiens idaltu; this subspecies became extinct, but was believed to have lived as long as 160,000 years previous). While the exact origin of humanity is a hotly contested paleontological debate, it is likely that the first humans evolved from a genus of upright ape-like hominids called Australopithecus (likely Australopithecus afarensis).

The current human race, Homo sapiens sapiens, is not the only human to have evolved on Earth, but the Homo sapiens sapiens species, modern humanity, are believed to have either displaced or outlasted all other branches of the genus. Evidence exists that there was significant contact between modern humans and other members of the genus, both cultural and genetic, coexisting with Homo erectus, Neanderthals and Homo floresiensis, and possibly interbreeding with non-modern humans. Modern humans usually stand 6' tall, though this varies depending on nutrition, genetics and other factors. Members of the species, like some Covenant species, are four-limbed and bipedal, which enables them to walk upright on two legs and use their arms and hands (including opposable thumbs) to hold and manipulate objects such as tools.

Early civilization and regression
Humanity achieved an advanced state early in its history, achieving a high level of technological sophistication and expanding outward along the galactic rim to escape Forerunner control thousands of years before the activation of the Halo Array, even warring against the Forerunners, a war which they did not win. As punishment, the humans were stripped of their technology, their civilizations smashed, and the remnants exiled to their homeworld, reduced to a pre-technological state from which they would be forced to start again.

Post-Array recovery
The development of human civilization as humans recognize it today started from the ability to harness the growth cycle of plants, producing edible food-energy in a systemic fashion. This time is referred to as the Neolithic Revolution, which occurred first on Earth over 10,000 years ago and soon spread to disparate human groups. The stability that came from systemic agriculture allowed for more permanent settlements and the development of ever-more-complex tools to further benefit the members of the species.

Innovated toolmaking and the domestication of other species on Earth gave human populations greater and greater power to expand their populations, and trade ensured the diffusion of new technologies to adjacent groups. These exploding populations led to the formation of the first genuine civilizations over 8,500 years ago. The sites of such early cultures are believed to have formed in Southwest Asia and Asia Minor, and appeared elsewhere soon after. The infrastructure of civilizations continued to expand and grow in complexity as innovative technologies and larger populations allowed for increasing food-energy availability. Economic, political and scientific advancement continued to quicken as this species was able to automate many tasks in the Industrial Revolution.

This automation gave birth to the Digital Revolution, in which computing machines allowed scientific discovery and technological development to accelerate with explosive speed. Larger urban centers and tools for civilian and military uses were able to develop, as were more modern economic and political systems. As these systems developed further, the species was able to enjoy longer, more pro-creative, and more comfortable lives, virtually impervious to other creatures from whose midst they sprang. Thus-unchecked, human population growth eventually led to the presence of several billions more humans on Earth than could be comfortably sustained, ultimately leading to a high demand for humans to expand out-world.

18th-20th century
The 18th through 20th centuries were times of drastic change for countries known as the "Industrial Revolution". As an unintended result of major political and economic ramifications due to the rise of constitutional governments and refined capitalist resource management techniques, important inventions such as the automobile, electrical devices like the radio, and aircraft went into widespread use at previously unheard of rates for human innovations. Revolutionary progress in humanity's understanding of medicine and chemistry was also being made during this era of turning points. Such important chemical engineering advancements included anesthesia which dramatically enhanced all surgical practices, and plastics that could cheaply fulfill an enormous amount of material roles (with the better preservation of food being one of its greatest functions). Prior to such chemical and medical advances, average humans at the beginning of this time span could expect a lifespan of approximately 45 years, but towards its end, thanks to the introduction of antibiotics and other medicines combined with better food production and preservation, the age-old scourge of widespread plague and starvation was becoming virtually a thing of the past, and enabling people to live well beyond 80 and even into 100 years of age.

Essentially, Mankind was growing ever more efficient in how it applied itself to previous sciences and arts, and the art of the military would prove no exception to this pattern. There would be a rapid change in armed conflicts, starkly different from the primitive melee-oriented wars of the past; after two massive wars within the first 50 years of the 20th century, humanity saw the invention of such technologies as superior firearms and automatic weapons, radar, tanks, missiles, jet engines, and ultimately the atomic bomb, which became the most powerful weapon then known. Atomic bombs ultimately led to nuclear warheads, which eventually became key components in human arsenals in the brutal war against the Covenant.

In the next 60 years the superpower nations of the United States of America and the Union of Soviet Socialist Republics (succeeded by the Commonwealth of Independent States) became highly competitive, leading to a period of military and cultural tension known as the "Cold War"; an arms race by which the lethality of humanity's relatively new warfare technologies would be further refined upon in their destructive potential and precision, complimented with ever evolving battlefield doctrines and tactics as both nations sought to intimidate the other, with the newly developed nuclear weapons playing a large part in this period. In the 1950s, the Soviet Union launched the earliest satellite and sent the first human, Yuri Gagarin, into space, officially making humans space faring, and entering Tier 5 in the Technological Achievement Tiers. The United States successfully placed the first human, Neil Armstrong, on the moon, and eventually surpassed the Soviet Union's space faring and military production capabilities, leaving their doctrines as the ones that would heavily influence the UNSC in later centuries.

Additionally, with the creation of the Internet in the late 20th century, achievements from that era would dramatically revolutionize communication and data processing, further streamlining mankind's rate of technological progress. World politics also changed, with the early history of the United Nations beginning during this time period. The religiously neutral nature of many of these constitutional style governments also saw a relative diminish in the weight of ideological dogma, with scientific and logical explanations for phenomena and methodology rising in importance. Religion would remain a staple of human societies insofar as advocating personal ethical codes, though unlike the Covenant its primary influence was no longer that of a mere framework to justify a large hierarchical system of differing castes and birthrights. In the later end of the 20th century, satellites were now using solar energy over primitive battery sources to power itself (as seen with earlier models) thus leading to a very long lifetime. And with this, satellites saw a much more massive and broader usage as means to send and retrieve data and communications, and additionally a method of navigation to both normal civilians as well as military purposes. Although much of the technology used during this time is disregarded as "primitive" by the standards of the 26th century, they were all somehow a precursor to all of technologies utilized later by the UNSC.

Colonization and war


The species was able to explore the space immediately surrounding their home planet in the 20th century, as the population began to advance beyond the capacity of the planet to comfortably sustain their civilization. The subsequent conflict over resources, economics, religion and politics on Earth gave way to numerous wars. Furthermore these tensions put great pressure on the species in the beginning of the twenty-third century, and the transnational organization that became the United Nations Space Command engaged in more frequent space colonization and sought to represent the entire species, even though no one state ever previously ruled the entire human race. The development of Slipspace travel in 2291 helped the UNSC engage in spreading the human race beyond their home solar system, relieving the serious ecological pressure on the home world.

Simultaneously, this expansion was also to usher in promising new opportunities for humanity, as some of these colonies, such as planet Reach with its bountiful titanium deposits, could offer abundant stores of raw materials that may had otherwise been considerably unique and scarce on Earth. With the initial advent of interplanetary trade driving down the costs of what may had once been an expensive implementation of their technology - such as the forging of space-worthy ships and naval vessels - the effects from these carefully implemented first colonization projects helped to ensure that interstellar trade, travel and communication were to be more commonplace amongst the general populace in the ensuring centuries, eventually granting humanity the capacity to expand to hundreds of worlds and establish colonies at enhanced rates.

The species as a whole was finally pushed into major conflict when, after several centuries of spreading throughout many solar systems and inhabiting hundreds of worlds,they discovered the violent, genocidal, theocratic Covenant, and were forced into the war covered by the Halo series. As the decades-long war wore on, the human species gained the reputation as a worthy adversary against the Covenant, despite the fact that they were technologically and numerically inferior.Humans could hold out on ground combat and often defeated the Covenant, but the Covenant in turn fled to space where they had virtually undisputed supremacy and glassed the planet.

Humans have been able to show great bravery when facing insurmountable odds. Some of the members of the Covenant wonder why the Hierarchs had refused to allow the humans to join them, as they had been able to hold steadfast even when outmatched in almost every way. However, despite great courage and brilliance, the future seemed dark for the survival of the human race as the Covenant continued to wipe out their colonies, marching ever closer to Earth. On October 20, 2552, Earth was found. In the ensuing battles over possession of Earth, humanity suffered heavy casualties.

March 3, 2553, saw the end of the Human-Covenant War as a victory for humanity and their new found Sangheili allies - the majority of the Covenant military having been defeated at Delta Halo by the Sangheilian Fleet, while the rest were annihilated by the joint Elite-UNSC forces at the Ark. This victory came in time to save the human home world, thanks chiefly to the actions of the Arbiter and Spartan John-117.

Technology
Prior to the Forerunner-Flood War, humanity had achieved a remarkably advanced technological state. Perhaps through their extensive contact with the Forerunners, humans had developed space travel and colonized many worlds outside of their solar system. However, all records and examples of this former technology were obliterated following the Human-Forerunner Wars, and human technology as we know it developed following the firing of the Halo Array.

In early stages, human technology and knowledge advanced through simple trial and error in an inefficient manner, hampering faster progress. Although humans had developed writing very early on in their history, it wasn't until the invention of printing that information and ideas could be mass-communicated in an effective manner. The development of the scientific method in later conjunction with improved and more efficient capitalistic resource management techniques during the lessons of the "Industrial Revolution" resulted in stark accelerations in the development of technologies and the acquisition of knowledge. New technologies were experimented and explored with advanced knowledge of underlying principles as talented individuals were better organized and better supplied, allowing extremely accurate and fast improvements to be made with minimized trials and costs. Such methods of thought and organization are a hallmark of humanity which differs from the Covenant who, lacking proper researching methods, would simply copy and reverse-engineer technology from ancient Forerunner artifacts via the Engineers, whilst generally having no understanding of the underlying concepts themselves. Thus it it is said that the Covenant are "imitative" while the Humans are "innovative" as the war progresses.

In the 26th century human technology did not advance equally for every concept previously explored. The most basic technologies (such as the ballistic weaponry and the wheel) had undergone few principal changes, the explanation for this being their proven reliability over centuries of use. The technology worked and so did not require heavy alteration or major changes. Humans however did have other great advancements such as Shaw-Fujikawa Translight Engines that are capable of reaching other star systems, as well as the creation of highly sophisticated AIs that could serve to fulfill a versatile amount of roles.


 * Weapons: While still primarily based on projectiles and chemical reactions, human weapons are still more advanced than the weapons of the 21st century. They come with a variety of electronic gadgets such as ammo readouts and are significantly more reliable, seldom malfunctioning. They are also generally immune to electromagnetic pulses. Still, there have been some advanced developments, such as the Magnetic Accelerator Cannon, which is extensively used on ships as well as on vehicles and ground based weapons. A similar weapon, the rail-gun, was experimented with in the 20th century. There have been developments in energy weapons such as the Spartan Laser and the experimental pulse lasers used on UNSC Prowler. Although some of these breakthroughs could have been based off of captured Covenant technology, humans have previously used laser technology. Humans may have a good understanding of particle beam technology but have yet to utilize it in their weaponry. One of the largest breakthroughs came in the mid 20th century where humans discovered that nuclear fission and fusion can be used as a weapon to cause a large explosion, with such warheads seen in many missile installations and UNSC warships during naval battles. Innovation in this area would also converge in the creation of humanities most devastating weapon during the war effort, known as the NOVA Bomb.


 * Vehicles: Though human vehicles still rely on crude wheeled or continuous track motion for locomotion, UNSC vehicles are still extremely advanced, incorporating high-strength materials with precision engineering to improve mobility and durability, while often mounting a variety of weapons or equipment to increase their flexibility. Most have switched from fossil fuels to hydrogen-fuel cell engines or at the very least use hybrid-electric engines for enhanced fuel efficiency. The most powerful of Human vehicles usually run on continuous tracks that allow them to better distribute their weight over uneven ground and to better grip uneven terrain thus allowing for the vehicles to go places where other wheeled counterparts could never, but the vehicles are usually heavier than their wheeled counterparts. However, the humans' armored units seen throughout the Halo series (i.e. Scorpions) have a small caliber cannon compared to even modern day MBTs. With only a 90 mm cannon, the UNSC Scorpion seems underpowered by today's standards, but there may be other advances not revealed which compensate for this, such as it's high rate of fire compared to today's tanks, and advanced ammunition.


 * Air Vehicles: Most UNSC aircraft are designed with Vertical Take-off and Landing capabilities, using adjustable jet engines for lift and thrust. It is possible that some incorporate Lifting Body principles.


 * Medical Advances: The use of Sterile Field Generators means that surgery is not only safer to perform, with a greatly reduced risk of infection, but is also able to be performed in the field. Combat personnel also use Biofoam, an expanding semi-organic compound that fills and pressurizes a wound, numbing it at the same time.


 * Space-Faring: During the Mid 20th century, Humanity experimented with rocket technology using it to build satellites and visit and subsequently colonize the Moon and beyond. With the advent of Slipspace engines allowing faster-than-light travel, the UNSC was able to expand well beyond the confines of the Solar System, colonizing a number of worlds. UNSC freighters transport food and goods between colonies, while UNSC Navy warships protect trade routes from pirates and defend colonies from enemy assault. However, the weapons and combat abilities of Human spacecraft are, as of the Human-Covenant War time period, still somewhat limited.

Population
Earth's population was deemed overpopulated in the 22nd century, jump-starting the colonization programs at the time. Despite the colonisation efforts made to resolve the overpopulation issue, Earth's population still remained in the billions. In 2511, Dr. Halsey and UNSC estimated the universal human population to be around 39 billion, of which many were unrecorded by colonial infrastructure. In October 2552, Cortana estimated that humanity suffered 23 billion casualties throughout the course of the Human-Covenant War, putting the surviving human population around 16 - 20 billion.

There has been some discrepancies regarding the population of Earth after the Human-Covenant War. According to the Bestiarum, the human population on Earth was stated to have been reduced to 200 million near the end of the Human-Covenant War, while the Halo Encyclopedia merely mentions the population to have been cut in half at the start of the Battle of Earth. The Encyclopedia does not however specify whether it means half of Earth's population were killed, or if a significant number were evacuated, although the latter is more probable, as the Covenant did not commence planetary bombardment, and the statement is in regard of the situation at the beginning and not the end of the battle. The actual casualty count during Battle of Earth was mentioned briefly in a ViDoc as being in the millions.

Anatomy and physiology
Humans are mammals, and are closely related to other large apes on the planet Earth. Like all placental mammals, they are warm blooded and give birth to live offspring, and nourish their offspring with milk. They have five fingers, one being an opposable thumb. This hand structure aided them in making tools early in their history.

Unlike Sangheili, their circulatory system is closed and consists of one heart and a network of blood vessels. They have red blood due to their iron-based hemoglobin, as well as two lungs which breathe mainly a nitrogen-oxygen based atmosphere. Externally they have more hair than most Covenant species, but not nearly as much as Brutes. They have an average sense of sight, but compared to Covenant species a poor sense of hearing and smell. They are omnivorous, meaning that they will eat both meats and plants, as well as consume high calcium foods, such as the milk of other animals.

Their bone structure is calcium-based and is designed to withstand moderate stresses, but is generally weaker than the skeletons of Jiralhanae and Sangheili. Their muscular system is, on average, also weaker than most large Covenant species. In theory at least, physical conditioning can still negate this somewhat as even a standard UNSC marine can be witnessed flipping a turned over vehicle, and with the right enhancements and equipment, overcome their physical disadvantages to an even further extent as demonstrated by the SPARTANs. If in extreme distress, humans can tap into hidden reserves of energy, known as an adrenaline rush thus giving them drastically increased strength. This response is known as the "Fight or Flight" reflex.

Connections between the Forerunners and humans
Until recently, it was popularly theorized among the Halo community that the Forerunners are the ancient ancestors of the Human species. Evidence of possible descent include the fact that only humans can take the Index from its resting place in the Library, as well as comments made by 343 Guilty Spark during the Halo trilogy. With the story of Human-Forerunner relations being revealed in Halo: Cryptum, it is now known that humans are not Forerunner descendants, although they are noted to have a strangely similar genetic code.

The Forerunners themselves were intrigued by the similarities between their own race and humanity. Because of their genetic and physical similarities, some Forerunner scholars theorized that humans were a kindred species, created by the Precursors in their own image, just as the Forerunners believed themselves to be.

It appears that the Forerunners chose humans became the inheritors of the Forerunner empire and technology because the Forerunners passed the Mantle of Guardianship down to humanity, as it was passed to them, presumably from the Precursors, and that the Forerunners re-encoded certain aspects of their technology (e.g. the Index) to only respond to human DNA.

In Halo: Combat Evolved, 343 Guilty Spark confuses the Master Chief with a Forerunner, referring to conversations they never had. In Halo 3, 343 Guilty Spark tells the Master Chief: "You are the child of my makers. Inheritor of all they left behind. You are Forerunner!" In addition, the Prophet of Truth also tells Sergeant Major Avery Johnson: "Your Forefathers wisely set aside their compassion. Steeled themselves for what needed to be done. I see now why they left you behind. You were weak. And gods must be strong." Quotes by the Gravemind spoken in Halo 3 also seem to reinforce the connection between humans and Forerunners, for example: ''Child of my enemy, why have you come? I offer no forgiveness for the father's sins, passed on to his son.'' However, the web comic that included the character N'chala makes this theory less likely. In the Iris viral campaign and the Terminals of Halo 3 explaining that the Forerunners discovered humanity on a planet in a "perilous location beyond the line" (Maginot Line, meaning that Earth was outside of the Forerunners' protection).

During the events in Halo: Contact Harvest, Covenant religious vehicles traveled the edge of Covenant-controlled space and discovered a planet that was covered with Forerunner "Reclamation" glyphs, who were actually the humans. Later, a report of the planet's glyphs was sent to the Vice Minister of Tranquility. He took the information to the Minister of Fortitude and they went to see the Oracle (the Forerunner AI, Mendicant Bias, in the Dreadnought). Upon activation of the Oracle, the AI proclaimed, "FOR EONS I HAVE WATCHED. LISTENED TO YOU MISINTERPRET. THIS IS NOT RECLAMATION. THIS IS RECLAIMER. AND THOSE IT REPRESENTS ARE MY MAKERS." Although humans are not, in fact, Forerunner descendants, the two San'Shyuum politicians interpreted Bias' statement as declaring humans to be Forerunners left behind during the Great Journey.