The Ecological Roles of Birds
Birds provide numerous invaluable ecological services, and one of the most important is by scattering plant seeds. Seed dispersal enables plants to migrate into new territory and reduces competition with others of their own species, thereby increasing survival rates. In fact, if you enjoy spicy foods, you owe some appreciation to birds, who played a pivotal role in the evolution of chili peppers. In an example of evolutionary partnership, chili plants evolved in a way that offers birds a nutritious food source, while the plants benefited from the wide distribution of their seeds after passing through the birds’ digestive systems. Capsaicin is the molecule in spicy peppers that creates the sensation of heat we feel when it binds to pain receptors in the mouth. On a human tongue, a solution of just ten parts per million creates a distinct sense of burning, but nerve receptors in birds do not register the heat of capsaicin even if they ingest as much as twenty thousand parts per million.
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