The Gaia theory posits that the Earth is a self-regulating complex system involving the biosphere, the atmosphere, the hydrospheres and the pedosphere, tightly coupled as an evolving system. The theory sustains that this system as a whole, called Gaia, seeks a physical and chemical environment optimal for contemporary life.
In Greek mythology, Gaia (/ˈɡeɪə, ˈɡaɪə/; Ancient Greek: Γαῖα, romanized: Gaîa, a poetical form of Γῆ (Gê), meaning 'land' or 'earth'), also spelled Gaea /ˈdʒiːə/, is the personification of the Earth and one of the Greek primordial deities. Gaia is the ancestral mother—sometimes parthenogenic—of all life. She is the mother of Uranus (the sky), from whose sexual union she bore the Titans (themselves parents of many of the Olympian gods), the Cyclopes, and the Giants; as well as of Pontus (the sea), from whose union she bore the primordial sea gods. Her equivalent in the Roman pantheon was Terra.
The Greek name Γαῖα (Gaia Ancient Greek: [ɡâi̯.a] or [ɡâj.ja]) is a mostly epic, collateral form of Attic Γῆ (Gē [ɡɛ̂ː]), and Doric Γᾶ (Ga [ɡâː]), perhaps identical to Δᾶ (Da [dâː]), both meaning "Earth". The word is of uncertain origin. Beekes suggested a Pre-Greek origin.
In Mycenean Greek Ma-ka (transliterated as Ma-ga, "Mother Gaia") also contains the root ga-.
Birth of Gaia, Uranus, and the Titans
Hesiod's Theogony tells how, after Chaos, "wide-bosomed" Gaia (Earth) arose to be the everlasting seat of the immortals who possess Olympus above. And after Gaia came "dim Tartarus in the depth of the wide-pathed Earth", and next Eros the god of love. Hesiod goes on to say that Gaia brought forth her equal Uranus (Heaven, Sky) to "cover her on every side". Gaia also bore the Ourea (Mountains), and Pontus (Sea), "without sweet union of love" (i.e., with no father).
Afterwards with Uranus, her son, she gave birth to the Titans, as Hesiod tells it:
She lay with Heaven and bore deep-swirling Oceanus, Coeus and Crius and Hyperion and Iapetus, Theia and Rhea, Themis, and Mnemosyne and gold-crowned Phoebe and lovely Tethys. After them was born Cronos (Cronus) the wily, youngest and most terrible of her children, and he hated his lusty sire.
Other offspring and the castration of Uranus
According to Hesiod, Gaia conceived further offspring with her son, Uranus, first the giant one-eyed Cyclopes: Brontes ("Thunder"), Steropes ("Lightning"), and Arges ("Bright"); then the Hecatonchires: Cottus, Briareos, and Gyges, each with a hundred arms and fifty heads. As each of the Cyclopes and Hecatonchires were born, Uranus hid them in a secret place within Gaia, causing her great pain. So Gaia devised a plan. She created a grey flint (or adamantine) sickle. And Cronus used the sickle to castrate his father Uranus as he approached his mother, Gaia, to have sex with her. From Uranus' spilled blood, Gaia produced the Erinyes, the Giants, and the Meliae (ash-tree nymphs). From the testicles of Uranus in the sea came forth Aphrodite.
By her son, Pontus, Gaia bore the sea-deities Nereus, Thaumas, Phorcys, Ceto, and Eurybia.
Because Cronus had learned from Gaia and Uranus that he was destined to be overthrown by one of his children, he swallowed each of the children born to him by his Titan older sister, Rhea. But when Rhea was pregnant with her youngest child, Zeus, she sought help from Gaia and Uranus. When Zeus was born, Rhea gave Cronus a stone wrapped in swaddling-clothes in his place, which Cronus swallowed, and Gaia took the child into her care.
With the help of Gaia's advice, Zeus defeated the Titans. But afterwards, Gaia, in union with Tartarus, bore the youngest of her sons Typhon, who would be the last challenge to the authority of Zeus.
According to Hyginus, Terra (Earth/Gaia), along with Caelus (Sky) and Mare (Sea), were the children of Aether and Dies (Hemera/Day). According to the mythographer Apollodorus, Gaia and Tartarus were the parents of Echidna.
The god Hephaestus once attempted to rape Athena, but she pushed him away, causing him to ejaculate on her thigh. Athena wiped off the semen and threw it on the ground, which impregnated Gaia. Gaia then gave birth to Erichthonius of Athens, whom Athena adopted as her own child.
Nonnus describes a similar myth, in which Aphrodite fled from her lustful father Zeus, who was infatuated with her. As Zeus was unable to catch Aphrodite, he gave up and dropped his semen on the ground, which impregnated Gaia. This resulted in the birth of the Cyprian Centaurs.
Gaia resented the way Zeus had treated her children, the Titans, so she brought forth the Gigantes to fight Zeus. It was prophesied that the Gigantes, who were born from Uranus's blood, could not be killed by the gods alone, but they could be killed with the help of a mortal. Hearing this, Gaia sought for a certain plant that would protect the Gigantes even from mortals. Before Gaia or anyone else could get it, Zeus forbade Eos (Dawn), Selene (Moon) and Helios (Sun) to shine, harvested all of the plant himself, and had Athena summon the mortal Heracles, who assisted the Olympians in defeating the Gigantes.
According to Hesiod, in his lost poem Astronomia, Orion, while hunting with Artemis and her mother Leto, claimed that he would kill every animal on earth. Gaia, angered by his boasting, sent a giant scorpion to kill him, and after his death, he and the scorpion were placed among the stars by Zeus. According to Ovid, Gaia for some reason sent the scorpion to kill Leto instead, and Orion was killed trying to protect her.
When Boreas, the god of the north wind, killed Pitys, an Oread nymph, for rejecting his advances and preferring Pan over him, Gaia pitied the dead girl and transformed her into a pine tree.
According to little-known myth, Elaea was an accomplished athlete from Attica who was killed by her fellow athletes, because they had grown envious of her and her skills; but Gaia turned her into an olive tree as a reward, for Athena's sake. Gaia also turned the young Libanus into rosemary when he was killed by impious people.
Zeus hid Elara, one of his lovers, from Hera by stowing her under the earth. His son by Elara, the giant Tityos, is therefore sometimes said to be a son of Gaia, the earth goddess.