Question: Information: - Prymnesium is a genus of haptophytes, including the species "Prymnesium parvum". The genus is a unicellular motile alga. It is ellipsoidal in shape one flagellum is straight and there are two longer ones which enable movement. - The haptophytes , classified either as the Prymnesiophyta ( named for Prymnesium ) or Haptophyta , are a division of algae . The names Haptophyceae or Prymnesiophyceae are sometimes used instead . This ending implies classification at the class rank rather than as a division . Although the phylogenetics of this group has become much better understood in recent years , there remains some dispute over which rank is most appropriate . - Algae (singular "alga" ) is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as "Chlorella" and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, "Spirogyra" and the stoneworts. - In biology, a species (abbreviated sp., with the plural form species abbreviated spp.) is the basic unit of biological classification and a taxonomic rank. A species is often defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is often problematic. For example, in a species complex, the boundaries between closely related species become unclear or disappear altogether. Other ways of defining species include similarity of DNA, morphology, or ecological niche. The presence of locally adaptive traits may further subdivide species into infraspecific taxa such as subspecies. - Seaweed refers to several species of macroscopic, multicellular, marine algae. - Chlorella is a genus of single-cell green algae belonging to the phylum Chlorophyta. It is spherical in shape, about 2 to 10 m in diameter, and is without flagella. "Chlorella" contains the green photosynthetic pigments chlorophyll-a and -b in its chloroplast. Through photosynthesis, it multiplies rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce. - Charophyta is a division of freshwater green algae. The terrestrial plants, the Embryophyta emerged within Charophyta, with the class Zygnematophyceae as a sister group. In some charophyte groups, such as Zygnematophyceae or conjugating green algae, flagellae are absent and sexual reproduction does not involve free-swimming flagellate sperm. Flagellate sperm, however, are found in stoneworts (Charales) and Coleochaetales, orders of parenchymatous charophytes that are the closest relatives of the land plants, where flagellate sperm are also present in all except the conifers and flowering plants. Fossil stoneworts of Devonian age that are similar to those of the present day have been described from the Rhynie chert of Scotland. - Prymnesium parvum is a species of haptophytes (=Prymnesiophyta). The species is of concern because of its ability to produce a toxin, prymnesin. It is a flagellated alga that is normally found suspended in the water column. It was first identified in North America in 1985 and it is not known if it was introduced artificially (e.g., an invasive species or missed in previous surveys). Toxin production mainly kills fish and appears to have little effect on cattle or humans. This distinguishes it from red tide, which are algal bloom whose toxins lead to harmful effects in people. Although no harmful effects are known, it is recommended not to consume dead or dying fish exposed to a "P. parvum" bloom. Prymnesium parvum of Haptophyta is sometimes termed a golden alga or a golden brown algae as is Chrysophyceae of Heterokontophyta but the taxonomy of algae is under complex revision leading to contradictions in terms especially in non scholarly texts such as those from state wildlife departments. - Kelps are large seaweeds (algae) belonging to the brown algae (Phaeophyceae) in the order Laminariales. There are about 30 different genera. - Spirogyra (common names include water silk, mermaid's tresses, and blanket weed) is a genus of filamentous charophyte green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is diagnostic of the genus. It is commonly found in freshwater areas, and there are more than 400 species of "Spirogyra" in the world. "Spirogyra" measures approximately 10 to 100m in width and may grow to several centimeters in length. After reading the paragraphs above, choose the best answer for the entity that related to 'haptophyte' with the relationship of 'taxon rank'. Choices: - division - form - genus - group - order - phylum - species
Answer:
phylum