Learning Objectives Chytrids This small group (~1000 species) is thought to be the most primitive of the fungi. Once all classified as Chytridiomycota, these early, aquatic fungi are now grouped into Blastocladiomycota, Chytridiomycota, and Neocallimastigomycota. Unlike all the other fungi,…
Learning Objectives Fungi play a crucial role in the maintenance of ecosystems. They are found in most habitats on Earth, though they are largely moisture-dependent. Their ability to exist in such a wide variety of habitats is often facilitated by…
Learning Objectives The Fungal Body Fungi have well-defined characteristics that set them apart from other organisms. Most multicellular fungal bodies are made up of filaments called hyphae. Hyphae can form a network called a mycelium, which is the thallus (body) of the…
The word fungus is from the Latin word for mushroom, which is also similar to the Greek word for sponge. Indeed, the familiar mushroom is a reproductive structure used by only some of the fungi. There are many fungal species that don’t…
Prokaryotes are unicellular organisms with circular DNA that lack a nucleus or other membrane-bound organelles. These organisms can be divided into two distinct evolutionary lineages: Bacteria and Archaea. Though Bacteria and Archaea share many traits, Archaea are considered more closely…
Learning Objectives Viruses are microscopic (see Figure for scale), acellular, and contain nucleic acids. Despite their small size, which prevented them from being seen with light microscopes, the discovery of a filterable component smaller than a bacterium that causes tobacco mosaic…
Learning Objectives Several different groups of prokaryotes form mutualistic relationships with plant roots. Nitrogen is an essential nutrient for plants, yet it is difficult to obtain in many ecosystems. Though it is abundant in our atmosphere, this form a nitrogen…
Learning Objectives Stromatolites The earliest fossils are interpreted to be unicellular organisms similar to modern day cyanobacteria, sometimes referred to as blue green algae. The most widely accepted of these fossils dates back to 3.4 billion years ago from the…
Learning Objectives Bacteria are prokaryotes that, along with several other distinctions, have peptidoglycan in their cell wall. These unicellular organisms are incredibly diverse and involved in all ecological processes across every ecosystem. Though most are too small to see with…
Learning Objectives When these microscopic organisms were first separated from bacteria in 1977. When their ribosomal RNA was sequenced, it became obvious that they bore no close relationship to the bacteria and seemed to be more closely related to the…