In this lecture, Sue Hartley explores the different ways plant-eating animals have evolved to adequately sustain themselves, and tackle plants' weapons of self-defence.
Whilst vegetation might help fill an empty stomach, it doesn't provide animals with all the nutrients they need to live and grow. Plant material is mostly cellulose, water and carbohydrate, and has very little fat or protein which are both vital to an animal’s diet. To add to the dilemma, plants have developed all sorts of self-protection mechanisms, which make it hard for animals to feast on them at the best of times.
Just like humans and other animals, plants need to communicate, particularly when they are under threat. But although these chemical defence mechanisms might save them from being eaten, it uses up vital energy that could otherwise be used for growth.