Lesson plan
Physoclisti
Physoclisti are, collectively, fishes that lack a connection between the gas bladder and the alimentary canal, with the bladder serving only as a buoyancy organ. Addition and removal of the gases from the gas bladder in such physoclistous fishes occurs through specialised structures called the gas gland and ovale respectively. The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development. This anatomical state (the physoclistous condition) is believed to be evolutionarily derived from the ancestral physostomous state. Some fishes, such as eels, are anatomically physostomous, but their gas bladders function similar to those of physoclists.
Article summary
Physoclisti are, collectively, fishes that lack a connection between the gas bladder and the alimentary canal, with the bladder serving only as a buoyancy organ. Addition and removal of the gases from the gas bladder in such physoclistous fishes occurs through specialised structures called the gas gland and ovale respectively. The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development. This anatomical state (the physoclistous condition) is believed to be evolutionarily derived from the ancestral physostomous state. Some fishes, such as eels, are anatomically physostomous, but their gas bladders function similar to those of physoclists.
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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.