Are organisms that can be

used as warning signals for

changes in an ecosystem.

Bioindicators

Explanation:

Indicator species and/or keystone species  

Explanation:

Indicator species are species (e.g., plants, animals, fungi) that can be utilized to determine changes in the environment. An indicator species can show the impact of pollution on an ecosystem. For example, mosses are indicator species that indicate the acidity in the soil. Moreover, keystone species are species that maintain the ecological balance in the ecosystem. When a keystone species is removed, the entire ecosystem is dramatically changed or may even cease to exist altogether. In consequence, keystone species can be used to define an entire ecosystem. For example, bees are a keynote species that contributes to balance the ecosystem by pollinating plants.

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.