Humans depend on plants in numerous ways. One reason we depend on plants is for consumption. Plants have the unique ability of producing their own food through a process called photosynthesis. In this process, plants are able to produce macromolecules such as carbohydrates that cannot be produced in animals or humans. In humans, the only to gain these macromolecules is to consume plant matter, or consume plant-eating animals (herbivores).
When humans consume plants, the carbohydrates, lipids, and proteins that are broken down through two forms of cellular respiration. The two processes of cellular respiration displayed in humans are anaerobic or aerobic. The deciding process used depends on the presence of oxygen. Cellular respiration converts the material into useable energy called ATP. ATP is the energy form that cells can use to perform their various functions and it can also be stored for later use. Without plants, none of this energy could be produced and the herbivores that humans consume would not exist.
The cells in plants also undergo cellular respiration, which creates the byproduct oxygen. Oxygen is required for human survival, and is required for efficient ATP creation. This means that humans not only need plants for eating, but also need their created oxygen to break the food down efficiently.
In humans, cellular respiration also produces heat also needed in the body for thermoregulation, Thermoregulation that is an example of temperature homeostasis in humans, requires heat energy to maintain a relatively constant internal temperature. All the heat energy that...