Organisms that must get their energy from food sources are called heterotrophs.

Here's why:

* Heterotrophs cannot produce their own food through processes like photosynthesis (like plants do).

* They rely on consuming other organisms (plants, animals, fungi, etc.) to obtain the energy and nutrients they need to survive.

* Examples of heterotrophs include animals, fungi, and most bacteria.

Let me know if you have any other questions about organisms!