Carnivorous plants exhibit nutritional adaptation because they have green leaves which shows they are Autotrophic but they grow in nitrogen deficient soil.So, to meet the nitrogen need these plants feed on insects to fulfil their nutritional requirement.

Example:In case of Pitcher Plant it is assumed that during the course of evolution the leaf folded inwards to form the inside of the pitcher .Now, this plant grows in nitrogen deficient soil and traps insects.These insects are digested inside the pitcher which has a digestive liquid and meet it’s nitrogen need.