Here's why:

* Autotrophs: These organisms, like plants and algae, use sunlight to create their own food through photosynthesis. They are also known as producers.

* Heterotrophs: These organisms cannot create their own food and instead obtain energy by consuming other organisms. They are also known as consumers.

Here are some examples of heterotrophs:

* Animals: They eat plants or other animals.

* Fungi: They absorb nutrients from decaying organic matter.

* Bacteria: Some bacteria are decomposers, while others are parasites that live off of other organisms.

Important Note: While heterotrophs don't need sunlight directly, they indirectly rely on it. The food they consume comes from autotrophs that have used sunlight to create energy.