Slime molds are fascinating organisms that have puzzled scientists for centuries. They are neither animals nor plants, nor fungi, but belong to a diverse group of protists that can live as single cells or form multicellular structures. One of the most common and conspicuous slime molds is Stemonitis, which produces brown, feathery fruiting bodies on rotting wood. But what is the evolutionary origin of Stemonitis and its relatives? Which of the following organisms is it most closely related to?
The answer is: other amoebas
According to Wikipedia, slime molds are classified in the supergroup Amoebozoa, which includes various types of amoebas and their relatives. Amoebas are single-celled organisms that move and feed by extending pseudopods, or false feet. They are found in many habitats, from freshwater to soil to human intestines. Some amoebas can form multicellular aggregates or colonies, such as the cellular slime molds and the plasmodial slime molds.
Stemonitis belongs to the plasmodial slime molds, also known as myxomycetes. These slime molds have a complex life cycle that involves a free-living single-celled stage called a swarm cell, and a multinucleate mass of cytoplasm called a plasmodium. The plasmodium can grow to several centimeters in size and crawl over substrates in search of food. When the plasmodium matures, it forms fruiting bodies that release spores, which can germinate into new swarm cells.
The plasmodial slime molds are more closely related to some amoebas than to other slime molds, such as the cellular slime molds and the protostelids. The cellular slime molds, such as Dictyostelium, spend most of their lives as individual amoeboid cells that feed on bacteria. When food is scarce, they aggregate into a slug-like structure that migrates to a suitable location and forms a stalked fruiting body. The protostelids are microscopic slime molds that form simple fruiting bodies with one or a few spores.
Why does it matter?
The phylogeny of slime molds is important for understanding the evolution of multicellularity and complex life forms. Slime molds are examples of convergent evolution, where similar traits arise independently in different lineages due to similar selective pressures. By comparing the genetic and molecular mechanisms underlying the development and behavior of slime molds, scientists can gain insights into how multicellularity evolved in other groups, such as animals and plants.
Slime molds are also useful models for studying biological phenomena such as self-organization, pattern formation, decision making, and learning. Slime molds can exhibit remarkable abilities, such as solving mazes, optimizing networks, and adapting to changing environments. By exploring how these simple organisms achieve these feats, scientists can learn more about the principles of biological computation and intelligence.
Slime molds are not only interesting for science, but also for art and culture. Slime molds have inspired artists, designers, and educators to create works that showcase their beauty, diversity, and creativity. Slime molds have also been used as metaphors for social and political issues, such as cooperation, conflict, democracy, and resistance. Slime molds challenge our conventional notions of life and intelligence, and invite us to rethink our relationship with nature and ourselves.
Stemonitis is a slime mold that belongs to the supergroup Amoebozoa, along with other types of amoebas. It is more closely related to some amoebas than to other slime molds, such as the cellular slime molds and the protostelids. Stemonitis and its relatives are fascinating organisms that have intrigued scientists and artists for centuries. They offer valuable insights into the evolution of multicellularity and complex life forms, as well as the principles of biological computation and intelligence. They also challenge us to appreciate the diversity and creativity of life on Earth.