Final answer:
Desert plants often have small leaves to reduce water loss through evaporation and transpiration, which is vital for surviving in a water-scarce environment. Features like a thick waxy cuticle and specialized photosynthesis aid in water conservation.
Step-by-step explanation:
Many desert plants have small leaves to conserve water. This adaptation is crucial because water conservation is a major requirement for survival in the harsh desert environment. Smaller leaves have a reduced surface area, which minimizes the loss of water through the process of evaporation and transpiration.
Plants like the ocotillo (Fouquieria splendens), found in deserts such as the Sonora Desert near Gila Bend, Arizona, have evolved not only to have tiny leaves but also to shed them in response to the lack of rainfall. Their leaves appear only after rainfall and are quickly shed to reduce water loss. Additionally, many desert plants have evolved other features like a thick waxy cuticle and specialized forms of photosynthesis that further aid in conserving water.