Methods Endocytosis occurs when individual cells take up food directly. Protozoa take in nutrients by diffusion across the cell membrane and by encapsulating food in cell membranes called food vacuoles that merge with lysosomes.
Arthropods have specialized cells in the green gland that are ameboid and aid in digestion.
Although vertebrates digest mainly in their hollow gut, absorbing by diffusion or active transport, we do have a few blood related cells that are still very ameboid in their feeding. Animals from protozoa to whales can be filter feeders . By definition, these animals select food based on size. A good example is found in bivalves which use their gills to filter passing water. Solid material sticks to a mucous track and is carried to the mouth by cilia where it is ingested.