Non-human life differs from that because the environments are covered with like sewers, buildings, and roads. Green spaces such as parks, backyards, and undeveloped lots are scattered in among the developed areas instead of all connected together. Plants and animals have to deal with exposure to toxins from vehicles and loss of habitat and food sources.
There would be less oxegen and also economically exploit us as 80% of things we use is from trees. we will be ruined, that's for sure.
Etioliation means that you water plants that are planted in an area with little to no sunlight. This results in weak stems, smaller leaves, yellow color, etc. The seedlings that are grown in the dark are known as "skotomorphogenesis." Etiolation comes from something called "Auxin's" and Auxin's are moved from the top of the plant to the bottom which creates lateral buds. Typically, etiliation results in the chances being raised for the plant to receive sunlight but causes underiable symptoms.
Best of Luck!