Slime molds are fungus-like protists that feed on dead plant material, bacteria, and fungal spores. They can form colonies of coenocytes, the largest single cells in the animal world. Slime molds belong to four distinct protist families and have different adaptive strategies and structures, such as the “ectoplasmic network” and pheromone release for colonial movement.
Slime mold is a broad categorization of fungus-like, slimy, amoeboid protists (unicellular eukaryotes, i.e. single-celled, non-bacterial organisms) that feed on wood, flowers, fruits, mulch, any other type of dead plant material, bacteria, yeast, and fungal spores. Individual slime mold organisms are usually microscopic, but some species form colonies of coenocytes that are usually a few centimeters across. A coenocyte is a large cell with many nuclei that occurs when nuclear division is not accompanied by cell division. In some cases, these coenocytes can grow in size up to 30 square meters, making them the largest single cells in the animal world, much larger than the ostrich egg, which is often erroneously cited as the largest cell.
Slime molds come in a variety of shapes, including irregular, spherical, bulbous, cylindrical, and colors, including bright pink, orange, yellow, white, gray, and brown. In some ways, their colonial behavior resembles the behavior of multicellular fungi, although technically they are colonies of single-celled organisms. Upon maturity, a slime mold colony forms a sporangium, a spore-filled bulb on a stem, which releases spores into the environment. These spores hatch both amoeboid and flagellate gametes which combine to create a zygote, which subsequently develops into a slime mold colony, depending on available nutrients.
The group of organisms called “slime molds” are polyphyletic, meaning they are not descended from a common ancestor. Although slime molds were initially misclassified as fungi, scientists now consider them to be non-fungal protists that belong to four distinct families: Mycetozoa (part of kingdom Amoebozoa), Acrasiomycota (part of kingdom Excavata), Labyrinthulomycota (“slime nets”, part of kingdom Chromalveolata), and Plasmodiophorids (plant parasites, part of kingdom Rhizaria). Interestingly, the four groups of “slime molds” are actually part of entirely different protist kingdoms, despite their shared qualities, which emerged as a result of convergent evolution.
Different groups of slime molds have different characteristic adaptive strategies and structures. For example, “slime webs” are so well known because they build networks of membrane-covered tubes and filaments that are used as tracks to guide cells, as well as absorb nutrients for them. This structure is known as the “ectoplasmic network”. A unique organelle called the Bothrosoma builds these filaments. Slime webs are more distantly related to other slime molds, with some scientists considering them their own group. Another group of slime molds, the Acrasiomycota, are known to release pheromones to aggregate amoeba cells in preparation for colonial movement.
Protect your devices with Threat Protection by NordVPN
