Outside factors seem to effect the Earth on some aspects and seem not to effect it on others.
For example, water tide is effected by the moon's gravitational force, and seasons effects by Earth's location and orientation in relation to the sun.
Some of the environment seems to result by processes internal to Earth's "closed system". For example, overpopulation occurs when a species' population exceeds the carrying capacity of its ecological niche. In this case, ecology plays as the "closed system" factor. Another example can be Drought, which can result from a number of causes based of the weather and climate of a region. In this case we can say those causes are bound to the "closed systemness" of Earth, and shape the problematic situation of drought.
Hope this is helpful :)
