Types, evolution and significance of plant - animal interactions

Interactions between plants and animals are analyzed starting from the advantages gained by animals and proceeding to those gained exclusively by plants. These interactions are essentially of five types: 1. predation of plants by animals; 2. benevolence of plants towards certain animals to prevent or reduce predation; 3. predation by plants (carnivorous plants); 4. symbiosis and mutualism; 5. seduction and deception of animals by plants for dispersal of plant reproductive structures. All types of plants are preyed on by animals, though fromas far back in evolution as algae, certain plantmolecules reduce or prevent predation. In themost primitive land plants, other types of interactions beneficial for plants are encountered.More evolved land plants (angiosperms) show all facets of the five types of interaction, whereas in prokaryotic and eukaryotic algae there is only predation and in some cases countermeasures to avoid it. An evolutionary path leading from predation, the original condition, to seduction, deception and carnivory, is also postulated.