Lesson plan
Halosphaera
Halosphaera is a genus of green algae in the order Pyramimonadales. Halosphaera is widely distributed in the plankton of oceans, and is found in both hemispheres. Halosphaera consists of two life stages: a non-motile coccoid stage, called the phycoma stage ( ), and a flagellated stage. The phycoma is spherical, up to 800 μm in diameter, with two layers of cell walls: The inner wall is pectin-like, while the outer wall is tough and sporopollenin-like. Mature phycomata contain a single nucleus and several numerous chloroplasts, in most species with pyrenoids. Pterosperma divides asexually in the phycoma stage, forming a large number of flagellate swarmer cells. Swarmers have four long flagella which arise from a pit in the anterior surrounded by four lobes. Each contain a single parietal chloroplast with two to four pyrenoids, and an eyespot. The cell body is covered with several types organic scales, and the flagella are also covered with multiple layers of cells. Flagellate cells can also divide by fission.
Article summary
Halosphaera is a genus of green algae in the order Pyramimonadales. Halosphaera is widely distributed in the plankton of oceans, and is found in both hemispheres. Halosphaera consists of two life stages: a non-motile coccoid stage, called the phycoma stage ( ), and a flagellated stage. The phycoma is spherical, up to 800 μm in diameter, with two layers of cell walls: The inner wall is pectin-like, while the outer wall is tough and sporopollenin-like. Mature phycomata contain a single nucleus and several numerous chloroplasts, in most species with pyrenoids. Pterosperma divides asexually in the phycoma stage, forming a large number of flagellate swarmer cells. Swarmers have four long flagella which arise from a pit in the anterior surrounded by four lobes. Each contain a single parietal chloroplast with two to four pyrenoids, and an eyespot. The cell body is covered with several types organic scales, and the flagella are also covered with multiple layers of cells. Flagellate cells can also divide by fission.
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.