Protists can be classified based on their ability to produce their own food. Those protists with chloroplasts are capable of photosynthesis, allowing them to convert sunlight into energy, much like plants. This group includes organisms such as algae, which harness sunlight to create their own food.
On the other hand, protists that lack chloroplasts are unable to perform photosynthesis and are therefore heterotrophic. This means they must obtain their nutrients by consuming organic matter or other organisms. This group often includes parasites and protozoans, which ingest their food to survive. Understanding this distinction helps us grasp the diverse ways in which protists interact with their environment and obtain energy.