1. Bacteria: These are prokaryotes, meaning they lack a nucleus and other membrane-bound organelles. They are incredibly diverse and found in almost every environment on Earth. Examples include *E. coli* and *Staphylococcus aureus*.

2. Archaea: Another type of prokaryote, archaea are often found in extreme environments like hot springs or salty lakes. They are distinct from bacteria in their genetic makeup and metabolism.

3. Amoeba: These are single-celled eukaryotes (have a nucleus) that move using pseudopodia (false feet). They engulf food through phagocytosis.

4. Paramecium: These are also single-celled eukaryotes, but they have a more complex structure than amoebas. They move using cilia, hair-like structures that beat rhythmically.

5. Euglena: These are single-celled eukaryotes that have characteristics of both plants and animals. They can photosynthesize like plants, but they can also move using flagella.

6. Yeast: These are single-celled fungi that are important in baking and brewing. They reproduce asexually by budding.