Cyborg

A cyborg  (short for cybernetic organism) was a being that was composed of both natural and artificial systems, ranging from prosthetics to implants to entirely mechanical casings operated by or sustaining the organic parts of that particular entity.

The term biomechanoid was also used to apply to cybernetic-biological integrations, such as the Dalek battle computer requiring a human to operate it, (TV: Remembrance of the Daleks) the Dragon that guarded Iceworld, (TV: Dragonfire) and the Ice Warriors. (TV: Cold War)

Cyborgs were sometimes victims of injury in which their biological bodies were damaged beyond their ability to heal. (TV: The Pirate Planet, Voyage of the Damned)

The Cybermen were examples of cyborgs which, due to widespread use of standard parts, could be considered a race.

Sometimes pure robots such as K9 Mark 2 and CCPCs were referred to as cyborgs. (TV: Liberation, The Bounty Hunter, Mutant Copper) K9 himself commonly referred to himself as a cybernetic organism. (TV: The Korven, Robot Gladiators)

History
Cyborgs were found throughout the universe. In Christmas 2008, cyborgs, such as Max Capricorn and Bannakaffalatta, were aboard the starship Titanic. It was spoken of how the society of the time despised cyborgs, although it was also mentioned cyborgs were beginning to get equal rights, such as the right to marry. (TV: Voyage of the Damned)

Known cyborgs
Known cyborgs and extent of alterations include:

Daleks
The Daleks were mutants in armoured polycarbide or Dalekanium shells. The armour protected a living creature on the inside, serving as life support as well as a weapon that was difficult to destroy. (TV: Remembrance of the Daleks, Genesis of the Daleks, et al.) Originally and generally Kaled in origin, (TV: Genesis of the Daleks) certain groups of Daleks were converted from humans (TV: Revelation of the Daleks, The Parting of the Ways, Asylum of the Daleks) and, in an alternate timeline, Draconians and Sontarans. (AUDIO: Master of the Daleks)

Davros was another Kaled who suffered horrible disfigurement. He rode in and was supported by an advanced chair which served as a life support system and could keep him alive in extreme circumstances and for very long periods of time. He had a prosthetic third eye and later a prosthetic hand. (AUDIO: Corruption, TV: Genesis of the Daleks, The Stolen Earth)

Cybermen
As a result of parallel evolution, the Twelfth Doctor noted that Cybermen were inevitable wherever there were people. Indeed, on various planets across the multiverse, people upgraded themselves into Cybermen, who proceeded to spread out and convert others. (TV: The Doctor Falls, Cyberwoman) In N-Space, the Doctor saw the Cybermen rise on Mondas, Telos, Earth, Planet 14, and Marinus. (TV: The Doctor Falls) Generally, humanoid bodies were adapted into cyber-form with various parts replaced. (TV: The Tomb of the Cybermen, Attack of the Cybermen)

In an alternate timeline, Silurians were partially upgraded by the Cybermen, becoming Cyber-Silurians. (COMIC: Supremacy of the Cybermen) In another in which they integrated and invaded the Federation universe, the Cybermen used Borg technology to upgrade Judoon, Klingons, Raxacoricofallapatorians and Vulcans. (TV: Assimilation²)

Through the use of nanobots, the Cybermen transformed humans into Cyberslaves, their flesh and bone converted into metal. (GAME: Blood of the Cybermen)

On the Earth of Pete's World, Cybus Industries, established by the terminally ill John Lumic, sought to convert humanity into what they classed as Human.2. Initially, human brains were cut free and then placed within a suit of armour. (TV: The Age of Steel) When they invaded the Earth of N-Space, however, the Cybermen upgraded whole bodies to save time. (TV: Cyberwoman)

Recreated Pete's World Cybermen utilised Cyberdogs, dogs with a mechanical head and legs. (COMIC: Enemy Mine)

Cybershades were drones used by the Pete's World Cybermen that were composed of a disembodied cat or dog brain placed within a suit of armour. They were incapable of speech, but could roar or howl with an electronically affected voice. (TV: The Next Doctor)

Through the use of Cyber-pollen, the Cybermen could convert the dead. (TV: Death in Heaven)

Time Lords originally eluded the cyber-conversion process, with the Eleventh Doctor noting that he was "not exactly compatible", (TV: Closing Time) only to nearly fall victim to the process later. (TV: Nightmare in Silver) With resources provided by Rassilon, Cybermen at the end of the universe proved able to convert Time Lords. (COMIC: Supremacy of the Cybermen) Similarily, allowed the Cybermen to convert Time Lord corpses in the ruins of Gallifrey, becoming CyberMasters. (TV: The Timeless Children)

Following the Cyber-Wars, the Cybermen, led by Ashad, strove to ascend to mechanisation, purging themselves of organic components starting with the Cyber-Warriors, becoming "robots" as the Master put it. As well as achieving their goal of full automation, it would spare them the effect of the death particle, created by the Cyberium to wipe out all organic life. (TV: The Timeless Children)

Others
The Toclafane were human cyborgs from a time near the end of the universe, whose heads were fused into mechanical spheres by the Master. They were brought to 21st century Earth and used to conquer the planet and suppress the human population. (TV: Last of the Time Lords)

The Zygons' artificially enhanced a creature known as a Skarasen, from which they derived sustenance. They used the creature to wreak havoc on oil rigs in the North Sea by planting beacons on them that the Skarasen was drawn to. (TV: Terror of the Zygons)

Bannakaffalatta was a cyborg from the planet Sto who had a cybernetic chest, suggesting replacement of vital organs. He was ashamed of his cyborg nature, as cyborgs were discriminated against on Sto. He was fond of Astrid Peth and died defending her and those they were with from the Heavenly Host. (TV: Voyage of the Damned)

Max Capricorn was also a cyborg from the planet Sto. Somehow, he wound up being just a head fused into a cybernetic casing. The casing could extend his lifespan greatly. He was voted out of Max Capricorn Cruiseliners by his own board, and was bent on revenge. He intended to use the Titanic to cause a slaughter on Earth, for which the entire board would be arrested. He was thwarted, and fell to his death into the ship's storm drive. (TV: Voyage of the Damned)

A cyborg simply known as "the Captain" possessed a cybernetic mask and arm, which replaced his original limbs after he was severely injured in a crash landing on Zanak. (TV: The Pirate Planet)

Cassandra O'Brien.Δ17 was, more-or-less, a human from the year five billion. She had undergone extensive surgery to prolong her lifespan until she was nothing more than a piece of skin stretched on a metal frame, connected to a brain in a jar. (TV: The End of the World, New Earth)

Peking Homunculus had the cerebral cortex of a pig with a robot body made to look like a dummy. The Homunculus was homicidally insane, and loved carnage and violence. When his master showed signs of weakness, he turned on him and attempted to kill everyone in the room. (TV: The Talons of Weng-Chiang)

Psi was a cyborg who identified as an "augmented human". He possessed a cybernetic-ally enhanced brain. He could download information directly to it, project information onto surfaces, and delete memories at will. (TV: Time Heist)

Tricky Van Baalen was a human cyborg with an artificial voicebox and eyes used to replace what he had lost in an accident. His memory, however, could not be replaced, and he was tricked into believing he was an android. (TV: Journey to the Centre of the TARDIS)

The Juggernauts were also cyborgs implanted with human DNA. (AUDIO: The Juggernauts) Birdie was likewise implanted with human DNA. (TV: Mutant Copper)

The Dragon which guarded the Dragonfire was a cyborg. (TV: Dragonfire)

Having a prosthetic face and rotating head, the Winders were cyborgs. (TV: The Beast Below)

Drake had a prosthetic hand. (TV: Fear Itself)

The Borg were a species with humanoid bodies augmented with cybernetic implants. (COMIC: Assimilation²)

Kahlers such as Kahler-Tek were given enhancements including a weapon built in the arm, a targeting system and the ability to teleport, albeit against their will. (TV: A Town Called Mercy)

Nardole had a cybernetic body. (TV: The Husbands of River Song) After he was decapitated, his head was "glued" back on a body by the Twelfth Doctor. (TV: The Return of Doctor Mysterio, The Pilot)

King Hydroflax was a cyborg, able to contain several other heads in his cyborg body. (TV: The Husbands of River Song)

Development
Most cyborgs originated as organic lifeforms who suffered bodily damage or loss of body parts, necessitating mechanical replacements.

The Cybermen originally were organics, but made themselves cybernetic in order to sustain their lives. (TV: The Tenth Planet, AUDIO: Spare Parts)

Daleks were originally humanoid organics. They became mutants encased in bonded polycarbide armour to survive a nuclear war and wipe out all other life. (TV: Genesis of the Daleks, Remembrance of the Daleks)

Not all cyborgs were originally organic. Both Mechanoids (AUDIO: The Juggernauts) and CCPCs (TV: Mutant Copper) were implanted with human DNA. The results were the Juggernauts and Birdie. (AUDIO: The Juggernauts, TV: Mutant Copper)

Psychology
Many cyborgs considered their form of life to be superior to organic life, in the case of the Cybermen they viewed this as a failing of organic life and sought to convert organics via a process of Cyber-conversion into beings such as themselves, or other beings similar such as Cybermats. (TV: Attack of the Cybermen, AUDIO: The Crystal of Cantus)

Other species, such as the Daleks considered themselves to be the superior beings and sought to exterminate or subjugate all other life in the universe that was not a Dalek. (TV: Genesis of the Daleks) Unlike the Cybermen they did not attempt to alter or convert other species into a Dalek life form. However the Daleks did experiment with bodily possession of humanoid beings, and elements of humanoid and Dalek "essences". (AUDIO: The Curse of Davros, TV: The Power of the Daleks) In extreme circumstances; the Daleks did convert humanoid species into Dalek mutants to be placed within a Dalek travel machine, in these circumstances it was due to necessity, unlike the Cybermen's motivations. (AUDIO: The Time of the Daleks)

Emotions
Some cyborgs had emotions, and others did not. Bannakaffalatta had emotional feelings of attraction, kindness, attitude, self-sacrifice, humour and taking offence. (TV: Voyage of the Damned) On the other hand, both the Mondasian and Pete's World Cybermen had their emotions removed via an emotional inhibitor placed within their chest plate, because emotions would "destroy" them. This was used by the Tenth Doctor, who stopped the inhibitors inside the Pete's World Cybermen from working, and Craig Owens, who, in his own words, "blew them up with love" for his son Alfie, overloading the emotional inhibitors. The Cybermen, who were once human, realised what they had become; they were driven insane and died. (TV: The Age of Steel, Closing Time) The opposite of the Cybermen's case occurred in the CCPC Birdie, who was originally a pure robot. The fact that he had emotions was a contributing factor to his cyborg status. (TV: Mutant Copper)

Research and study
Many scientists of various species studied cybernetics, including Dr Tanizaki, (TV: Cyberwoman) Professor Alistair Gryffen (TV: Regeneration) and Davros. (AUDIO: The Juggernauts)

Cybernetics was a branch of knowledge on Gallifrey, indeed studied and mastered by the Doctor. (TV: Destiny of the Daleks)