The examination of the ecology of interacting plants and animals by using an evolutionary, holistic perspective. Plant–animal interactions can take many forms. For example, the chemistry of defensive compounds of a plant species may be altered by natural-selection pressures resulting from the long-term effects of herbivores. Also, the physiology of modern herbivores may be modified from that of thousands of years ago as adaptations for the detoxification or avoidance of plant defensive chemicals have arisen. Other examples of plant–animal interactions include pollination biology, fruit and seed dispersal ecology, herbivory on plants by invertebrates (such as insects) and vertebrates (such as ungulates), ant–plant interactions, the ecology and evolution of carnivorous plants, and community and ecosystem patterns of animal distributions resulting from the availability of plant resources.