Not all organisms feed the same. Some make their own food and energy, such as photosynthesising plants. These are autotrophs meaning they make their own nutrients, either through light energy or chemical energy.
Some bacteria living in extreme conditions such as deep sea vents rely on chemical reactions to derive energy. Although still autotrophic, these are chemoautotrophic while the photosynthesising organisms are photoautotrophic. Both are under the autotrophic umbrella.
Organisms that cannot make their own organic molecules using simpler molecules found in their environment, rely on feeding on those that can. These are heterotrophs and include humans. Since heterotrophs lack any ability to convert light energy or the electron donating potential from certain chemicals into reactions to produce the carbohydrates, lipids and proteins needed for life, they extract them from primary producers such as plants, or other heterotrophs at…