It is commonly believed by followers of monotheistic religions that the original being (God /Creator) who began all processes of creation, single-handedly created the Earth and all life upon it.
This is a simple belief that satisfies many, but the reality is we have no way of knowing the truth of this matter, unless we have memory of this event occurring- which I know of none that claim to have.
In reality, there is no reason to believe that the original Creator is responsible for every individual act of creativity that has occurred since the original movement from formless being into the creation of worlds.
Clearly, humans are also creative beings, responsible for having a dramatic effect on the world around them, and so, similarly, it is possible that the original Creator may have given birth to additional creative beings who went on to create other beings, worlds, and forms of life to inhabit these worlds.
In other words, the original Creator may have delegated further creation to a variety of beings that "He" created. We would call these beings gods due to their greater creative powers than we humans and if these gods possess free will then the worlds they create would be their responsibility and not the responsibility of the original Creator.
There is no reason to suggest that the physical universe was the work of one creative mind. It may be the work of several or even a vast number of creative minds. If so, the universe would be the combined responsibility of all these creative beings rather than the responsibility of the original creator just as the situation on Earth is the combined responsibility of the individual free will beings living upon it.
Many people struggle to understand why a supposedly loving God would create diseases, nuisance insects and the battle for survival we see on Earth. The answer may be that the situation on Earth and the life forms that exist upon it may be the work of a large variety of creative beings who may not always have created in a "Godly" way. That is, some may have created out of ignorance or even ill-will. The truth is, we have no way of knowing first hand. But what we do know is that if all life forms were created by beings other than the original Creator then these beings bear responsibility for them.
For more on this topic see the work of Matthew Ward and Kim Michaels, amongst others.