Gaia is the mother Earth. It is the idea that the Earth is an independent entity. Humans are like the cells of this entity. In fact, every living being on Earth are a part of Gaia. It looks like our cells and our metabolism system in our body. The Earth is a body and life is the metabolism system. In fact, this theory is old as humans are. Indeed, many traditions believed that the Earth was the whole and each individual were part of it. It is why in these traditions, each individuals must protect the Earth as it was their mother. Nowadays, ecologists think the same. We are part of the biosphere, part of the Earth and if we hurt the Earth, we hurt ourselves. In the same time, some scientists showed that it is in fact possible to see the Earth as a whole living system. Here we will see the different aspect of this theory.
First of all, two kind of Gaia theory is currently debated. The first one (which can be called the weaker version) is undeniable. It just said that because living beings transform their environment, this environment which is the Earth is linked with the biosphere. It means that they form a whole (which is called Gaia). This whole is interpreted as a living system in the stronger theory. Gaia born, maintains itself and evolves. The birth have been occurred long time ago during the creation of the Solar System. It also get later or in the same time a sister or more probably a partner, the Moon. This moon have actually a great importance in the apparition of life. Indeed, without it, it would maybe never have been life on Earth, at least it wouldn’t be the same as we know it. Earth and Moon could be see as a couple and their children as the biosphere.
Gaia evolves constantly like any living being from birth to death. Gaia evolves in different aspect known as biosphere (Darwin evolution), lithosphere (geology), hydrosphere and the atmosphere. Also, some talks about the noosphere. Since human being came into existence, the noosphere born and evolved since then. Inside the noosphere, the thoughts are shared and interact. Gaia have a body (lithosphere, hydrosphere, atmosphere), she (it is often seen a feminine being) is living (biosphere) and she is thinking (noosphere). We often talks about pollution. If humans are really part of the system, Gaia should maintains and keep under control our actions, So pollution shouldn’t really exist, it would be just a transformation in the Gaia’s body (we could even call it an evolution). But maybe we come from outside the system like viruses and we use Gaia to live but we aren’t part of the system. The Gaia theory sounds more fun. Who want to be compared as viruses?