Final answer:
Plants utilize adaptations such as bark, waxy cuticles, mechanical defenses like thorns and spines, and chemical defenses like toxins to decrease herbivory. If external defenses fail, they employ toxins and enzymes for protection. Adjusting growth and reproductive cycles, as well as establishing mutualistic relationships, are also strategies used by plants.
Step-by-step explanation:
Physical Adaptations in Plants to Decrease Herbivory
Plants have developed a variety of physical adaptations to decrease herbivory and ensure their survival. The primary defense mechanism includes an intact barrier such as bark and waxy cuticles that protect plants against predators.
Additionally, many plants have evolved mechanical defenses like thorns and spines, which are modifications of branches and leaves respectively.
These structures not only cause physical pain but may also induce rashes and allergic reactions in animals.
When these external defenses are compromised, plants can resort to secondary defenses like toxins and enzymes to deter herbivores.
For instance, the foxglove produces digitalis, a compound which is highly toxic if ingested. Moreover, certain plants may use phenology, adjusting growth patterns and reproductive cycles to minimize the impact of herbivores.
Lastly, some plant species engage in mutualistic relationships where herbivory plays a role in seed distribution, aiding in the plant's reproduction cycle, creating a balance within the ecosystem.