Ammonotelic, ureotelic, uricotelic: kaun sa animal kis group mein? Marine fishes and tadpoles are confusing me

8 answers & replies

• [+][–]Lakshmi TripathiDropperSample· 1mo ago

  Your notebook line is correct, keep it exactly like that. Ammonia: very toxic and very soluble, so it needs a lot of water to flush it out and is only safe for animals surrounded by water. Urea: much less toxic, needs moderate water. Uric acid: almost insoluble, least toxic, comes out as a paste or pellet with very little water, but it is the most expensive to make.

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• [+][–]Siddharth RaoDropperSample· 1mo ago

  Number 1 trips everyone. NEET follows the NCERT line: bony fishes are ammonotelic, and "marine fishes" are listed with the ureotelic group. In practice the marine ones that rely on urea are the sharks and rays (cartilaginous fishes), which keep some urea in the body to hold their body fluids at an osmolarity close to seawater. NCERT also mentions that some urea may be retained in the kidney matrix to maintain osmolarity in some ureotelic animals. So don't try to resolve it by logic, just learn it as two separate lines. If an option says "marine fishes: ureotelic", it's matching the book, mark it.

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• [+][–]Mehak AroraDropperSample· 1mo ago

  For the frog I think the tadpole is ureotelic because it stays in water, and the adult is ammonotelic because adult frogs have moist skin that lets ammonia leave. That's how I remember it, since water animals do ammonia and ... wait, that doesn't sound right. Someone correct me please, I always panic on this one 😬

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  • [+][–]Kavya NaikDropperSample· 1mo ago

    Mehak, you swapped it, it's the other way. Tadpole lives in water so it is ammonotelic. The adult frog lives mostly on land, and NCERT lists "many terrestrial amphibians" under ureotelic, so the adult is ureotelic. The change happens at metamorphosis: when the animal starts spending time on land, it can't flush ammonia continuously, so it starts converting ammonia to urea in the liver instead.

    Hint: whenever a question says "terrestrial amphibian", think urea. "Aquatic amphibian" think ammonia.

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    • [+][–]Yash Tiwari11thSample· 1mo agoAuthor

      Ahh samajh aaya, tadpole = ammonia, adult frog = urea. Thanks didi 🙏 notebook me circle kar diya

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• [+][–]Tanvi Deshmukh12thSample· 1mo ago

  Table time!! 📋

  Type	Examples (NCERT)	Water needed	Toxicity	Energy to make
  Ammonotelic	bony fishes, aquatic amphibians, aquatic insects	very high	highest	lowest
  Ureotelic	mammals, many terrestrial amphibians, marine fishes	moderate	medium	medium
  Uricotelic	reptiles, birds, land snails, insects	very low	lowest	highest

  For your Q3: yes uric acid costs more energy to make, you're right, but the animal gains by not losing water. Birds and reptiles lay shelled eggs on land where the embryo can't get rid of waste into water, so a solid, non-toxic waste that can sit inside the egg is practically ideal. Exact reasoning for the exam: "conserves water".

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  • [+][–]Yash Tiwari11thSample· 1mo agoAuthor

    Table bhi screenshot kar liya Tanvi didi, mock me ye paste karne ka mann hai 😂 thanks sabko

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• [+][–]Aarav Kulkarni11thSample· 1mo ago

  Class 11 here too, just adding one thing I noticed in my own notes: the urea is formed in the liver (ornithine cycle), released into the blood, and then the kidney filters it out. NCERT says the kidneys play a very minor role in excreting ammonia, because ammonotelic animals usually lose it directly by diffusion across the body surface or gill surfaces, as ammonium ions. So the kidney is important mostly for ureotelic and uricotelic animals.

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