Learning Objectives Brown algae (class Phaeophyceae) and diatoms (class Bacillariophyceae) belong to the phylum Ochrophyta. They are the result of a secondary endosymbiosis between a heterokont and a photosynthetic eukaryote. Heterokonts, such as the Oomycota, are united by the presence…
Learning Objectives There are currently around 2,000 species of dinoflagellates. They are unicellular, though dinoflagellates exhibit extensive morphological diversity and can be photosynthetic, heterotrophic, or mixotrophic. In photosynthetic dinoflagellates, most use the pigments chlorophylls a and c. Many dinoflagellates are encased…
Photosynthetic lineages can be found across the phylogenetic tree of protists. Most of the groups are unrelated to each other, as each major lineage acquired its chloroplast (and therefore the ability to photosynthesize) from different endosymbiotic events. For example, red…
Learning Objectives The water molds, phylum Oomycota (“egg fungus”), were so-named based on their filamentous morphology and their use of glycogen as a storage carbohydrate. However, molecular data have shown that the water molds are not closely related to fungi. As diploid spores, many…
Learning Objectives Slime molds are an unusual group of organisms that have previously been classified as animals, fungi, and plants. Like plants, slime molds have cellulose in the cell walls of their spores. Unlike plants, slime molds are heterotrophs! Though they were formally…
Heterotrophic organisms must consume organic matter to obtain energy. Under the umbrella of protists, there are several heterotrophic groups. Some of these are closely related to photosynthetic lineages of protists that have obtained chloroplasts via endosymbiotic events, such as Oomycota…
Learning Objectives What are Protists? The term “protist” is a general description for eukaryotic organisms that are not animal, plant, or fungus. These organisms were formerly classified in Kingdom Protista. As we have come to learn about genetics and the…
Fungi are heterotrophic eukaryotes with cell walls made of chitin and plasma membranes containing ergosterol. They can be unicellular (yeasts) or filamentous, forming a hyphal thallus called a mycelium. The hyphae can be coenocyctic or septate (with cross walls). Many…
Learning Objectives Although we often think of fungi as organisms that cause disease and rot food, fungi are important to human life on many levels. As we have seen, they influence the well-being of human populations on a large scale…
Learning Objectives The majority of described fungal species belong to the Phylum Ascomycota. Fungi in this group have simple septate hyphae and most produce fruiting bodies called ascocarps (Figure ) for sexual reproduction. Some genera of Ascomycota either only reproduce asexually via conidia…