A symbiotic relationship, or symbiosis, is any type of a close and long-term biological interaction between two biological organisms of different species, termed symbionts. There are three main types…

• Parasitism: symbiosis where one species benefits, and the other is harmed. Examples include both internal (e.g., worms) and external (e.g., ticks) parasites found on livestock like cattle, sheep, goats, and pigs. Some of these can be zoonotic (passed on to humans).
• Commensalism: symbiosis where one species benefits, and the other is neither harmed nor helped. An example is birds, such as cattle egrets, perching on or near grazing cattle and eating insects stirred up while they graze.
• Mutualism: symbiosis where both species benefit. Examples include pollination of flowering plants by animals, mycorrhizal interactions between a plant’s roots and fungi, and the relationship between leguminous plants and nitrogen-fixating bacteria.