The radiolarians are the last subgroup of the SAR clade, and these are mostly unicellular amoebas that use pseudopodia for feeding. Radiolarians contain an internal silica skeleton-like structure, and they have pseudopodia projections that they use for feeding on microorganisms. You can see an example of a radiolarian here; this is the main part of the organism with an internal silica skeleton-like structure, and these are the pseudopodia that are projecting outward to feed on microorganisms. For foraminifera, they have calcium carbonate shells with little holes through which pseudopodia can emerge. Some of these organisms have cells that contain multiple nuclei. The theme here is pseudopodia used for feeding. Next, we have the Cercozoans, flagellated protists that also use pseudopodia for feeding. The major theme of this group is feeding with pseudopodia.

Lastly, we are going to talk about Opisthokonta, a group that includes fungi and animals, hence not exclusively protists. However, it does include a notable group of protists known as Amoebozoa. To this point, we have used the term "amoeba" somewhat loosely; however, Amoebozoa refers specifically to amoebas that have lobe- and tube-shaped pseudopodia. Here are a few examples of Amoebozoa; these organisms depicted are slime molds. One type, sometimes called the dog vomit slime mold, is a plasmodial slime mold. This yellow mass is one massive continuous cell containing thousands of nuclei. The cell is compartmentalized into smaller sections rather than being one vast cytoplasmic section. It reproduces through fruiting bodies, which I will discuss more when we talk about fungi in a later video.

The other type is the cellular slime mold, which forms fruiting bodies by aggregating smaller individual cells. You can see a fruiting body forming here; all these tiny dots represent individual cells aggregating to form this large structure. This aggregation results in the formation of fruiting bodies, the mechanism through which these slime molds reproduce. While plasmodial slime molds form fruiting bodies as one continuous cell, cellular slime molds do so through the aggregation of many individual cells.

The diverse and varied nature of protists is a key point I want to convey. Protists are an assorted group in terms of morphology and life cycles because they represent a sort of 'catch-all' category for eukaryotes that aren't categorized as plants, animals, or fungi. This diversity underscores the lack of unifying themes within this group. I hope this overview gives you a broad sense of the diversity inherent in the group of organisms known as protists. See you in the next video.