Is Earth an organism? Since there is no unequivocal definition of life, the current understanding is descriptive. To define Earth as an organism, your answer most show either via observed phenomena or theoretically observable phenomena that Earth exhibits all or most of the following traits: Homeostasis, Organization, Metabolism, Growth, Adaptation, Response to stimuli, and Reproduction.
This lead to a stabilisation of the planets systems again, although, it may have gone too far, and swung back to a glacial period (although not a frozen earth), then moving back to a warm period before stabilising due to the tectonic movement of the continents northwards The break-up of Rodinia, birth of Gondwana, true polar wander and the snowball Earth
I hope this long ramble illustrates how there are a number of complex systems which all interact with each other to maintain conditions. Whether we consider the sum of these systems an organism is an ongoing discussion, but, all organisms have the ability to regulate via various systems, and each of these systems has the potential to lead to chaotic positive feedbacks, and spiral out of control, although negative feedbacks usually keep everything running as normal.
I have linked the Gaia theory webpage, and if you search for Daisyworld model, you will find a model which you can run to simulate feedbacks It is up to you whether you think this collection of feedback systems is an organism, and this debate will likely run for decades more.
While at present we have no record of living creatures having replicated a planet it is certainly plausible, and therefore it is plausible that the Earth is a living organism, given that it is possible for it to reproduce and self regulate through negative feedback mechanisms observable in nature.
"Emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors which emerge only when the parts interact in a wider whole" (https://en.wikipedia.org/wiki/Emergence).
The properties that we often associate with life are not specific to life, but to complex systems with emergent properties. Therefore, exhibiting specific properties commonly associated with life doesn't imply the Earth is alive (although it does not deny it). Whether it fits into the definition of an organism, it's again just a matter of definition. There's, however, no doubt that the Earth is yet another example of a complex system giving rise to emergent properties, which is why it allows us to refer to it as an organism or as an alive entity sometimes.
See also: https://en.wikipedia.org/wiki/Self-organization and https://en.wikipedia.org/wiki/Complexity. Again these concepts are commonly associated with alive organisms but are not exclusive to them. I think the problem here might be that, although these properties are not only of alive organisms, they are many times among the characteristics that we use to define what life is. Again, this is mostly a matter of definition.
The Earth is not a living thing and therefore not an organism. Life is defined by several things:
It is valid to say that earth is giant habitat for life. Earth can be described as a huge magnet and a hot rock orbiting a giant sun that will one day wipe out life on Earth. All human life is projected to be extinct between 5,100 and 7.8 million years from now Source