From a philosophical viewpoint, the synthesis of substances by plants and their transfer to animals is interesting. Clearly the substances produced by plants mostly provide some benefit to the plant. However, in some cases the plant will synthesise chemicals, such as nectar, specifically to attract animals, such that they can then be used to spread pollen. Many substances from plants are useful to animals, and so the question arises, as to why all plants are not poisonous? This would allow the plant to avoid predation by herbivores and this would be a survival advantage. Clearly when animals eat plants they derive some beneficial health effects but at the same time some animals such as grazing animals can cause significant damage to the plants. The synergism in nature that exists between plants and animals is hard to theorise from a scientific position unless you accept the notion that the plants have been provided for the animals to eat. As well as energy, plants also produce medicine for animals and yet there is no reason for them to do this.
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