Final answer:
Multicellular organisms use aerobic respiration to fulfill their high energy demands, which requires oxygen to produce ATP. The development of specialized respiratory structures has enabled complex and larger life forms to thrive. Efficient respiration is crucial for the dominance of aerobic organisms on Earth.
Step-by-step explanation:
Multicellular organisms that have high energy demands typically use aerobic respiration to meet their metabolic needs. This type of respiration is efficient at acquiring metabolic energy, allowing organisms to grow larger in size and become more complex. In aerobic respiration, oxygen is critical for obtaining energy in the form of ATP, using organic molecules such as carbohydrates (or biomolecules like proteins that can be converted into carbohydrates). The importance of oxygen for an organism's metabolism is apparent across the evolutionary tree, where various organisms have developed specialized structures like gills and lungs to obtain oxygen and support larger body sizes.
The ability to perform efficient respiration is also seen in animals like birds, which have evolved unique respiratory systems that allow them to fly and obtain sufficient oxygen even in high altitudes where oxygen levels are low. Hence, the evolution of aerobic respiration and the adaptations that have come with it have been vital for the dominance of aerobic organisms on Earth, contributing to the diversity of life forms we see today.