plastidären

Plastidären is a term that appears in some Swedish-language sources to refer to organisms that carry plastids, the organelles used in photosynthesis and other biosynthetic processes. As a descriptive category, plastidären includes plants, algae, and many protists that retain plastids derived from endosymbiotic events.

Taxonomic status: Plastidären is not a formal taxonomic group in contemporary classifications. It is a broad, descriptive concept that spans multiple eukaryotic lineages united by the possession of plastids.

Origin and diversification: Plastids originated when a eukaryotic host cell incorporated a cyanobacterium. Primary endosymbiosis produced plastids in the Archaeplastida lineage, including glaucophytes, red algae, green algae, and land plants. In other eukaryotes, plastids often arose by secondary or tertiary endosymbiosis, leading to a variety of plastid forms with extra membranes.

Structure and function: Plastids vary in color, structure, and metabolic roles. Chloroplasts carry out photosynthesis; non-photosynthetic plastids (such as amyloplasts, leucoplasts, and chromoplasts) perform other biosynthetic tasks, including storage and pigment production. Some parasites also retain vestigial plastids, known as apicoplasts, with essential metabolic functions.

Current usage: The term plastidären is not widely used in current taxonomic practice; modern work typically references explicit clades or the origin of plastids (primary or secondary endosymbiosis) rather than a single umbrella group. It serves mainly as a conceptual shorthand for plastid-bearing eukaryotes.