Some protists obtain energy through photosynthesis while others do so by digesting either hunted food or decomposing matter. Protists are a diverse group that consists of plant-like, animal-like and fungi-like organisms. Algae are plant-like organisms, which use photosynthesis to make food.
When an organism can produce its own food, it is called an autotroph. Photosynthetic algae are autotrophs.
Animal-like protists are called protozoa, which include organisms like the paramecium, and amoeba. Protozoa obtain energy by eating food from their environment. These organisms engulf food and use food vacuoles to digest it. Slime molds are fungi-like organisms that thrive and get energy through the digestion of dead matter. Protozoa and slime molds are heterotrophs because these organisms need to consume other organisms to obtain energy or nutrients.