Kingdom Protoctista
Kingdom Protoctista is the term used to describe a category of living organisms that are unable to be defined as a plant, animal or fungus. Protists, slime and algae can all be considered part of kingdom Protoctista.
Protists
Protists are unicellular organisms. Derived from the word protista, which means ''the very first,'' the organism can be traced back to being around on the earth over two billion years ago. There are over 80 types of protists that mainly situate themselves within water.
Slime
Slime is more commonly referred to as slime mold. There are two types of slime: plasmodial and cellular. Plasmodial slime mold is a large single-celled mass with thousands of nuclei. It is usually brightly colored and can be found in moist, cool and shaded locations. Cellular slime molds are also single-celled; however, they can adapt due to a chemical reaction, which forms multicellular slugs.
Algae
There are several thousand different types of algae. Some of the most common are blue-green, green, red and brown and black algae. The majority of algae are single-cell organisms. Algae sit on the surface of water all over the globe. They often have a furry texture, and can be found on rocks, coral or plant leaf. There are three different types of algae. Microscopic algae float along with currents within the water. Filamentous algae are made up of long strands that form within the water. Attached-erect algae form on surfaces in or near the surface of the water.