AP BIOLOGY

Detailed explanation-1: -Pheromones. A pheromone is a secreted chemical signal used to trigger a response in another individual of the same species. Pheromones are especially common among social insects, such as ants and bees. Pheromones may attract the opposite sex, raise an alarm, mark a food trail, or trigger other, more complex behaviors.

Detailed explanation-2: -Some chemical signals are derived from steroid hormones and are used to inform receivers about the sex and reproductive state of the sender. New displays sometimes evolve from other displays in the species’ signal repertoire.

Detailed explanation-3: -Structures such as the long ornamented tail of the peacock, the roaring sounds of howler monkeys, audible kilometers away, and the pheromone trails laid by ants to guide their nestmates to resources are each examples of animal signals (Figure 1).

Detailed explanation-4: -Many animals use chemical communication or pheromones to communicate. They may leave their scent to mark territory or attract mates. They often use smell to find prey and identify other animals.

Detailed explanation-5: -There are five categories of chemical signaling found in multicellular organisms: direct, autocine, paracrine, endocrine, and pheromone.