A likely explanation is that more variations accumulated by more chloroplasts in cells of sun plants.

In other words, lets carnivorous plants do what all plants do: carry out photosynthesis, that is, grow by harnessing energy directly from the sun.

Rainforests have their own perfect system for ensuring their own survival; the tall trees make a canopy of branches and leaves which protect themselves, smaller plants, and the forest animals from heavy rain, intense dry heat from the sun and strong winds.