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This table shows the results of the analysis of urine samples of three organisms - HSC - SSCE Biology - Question 20 - 2005 - Paper 1
Question 20
This table shows the results of the analysis of urine samples of three organisms. | Organism | Terrestrial mammal | Freshwater fish | Marine fish | |--... show full transcript
Worked Solution & Example Answer:This table shows the results of the analysis of urine samples of three organisms - HSC - SSCE Biology - Question 20 - 2005 - Paper 1
Step 1
Urine concentration of Terrestrial mammal
Answer
Terrestrial mammals produce concentrated urine. This adaptation helps them retain water in a terrestrial environment where water may be scarce. The concentrated urine is primarily composed of urea, which is energetically less costly to excrete than ammonia.
Step 2
Urine concentration of Freshwater fish
Answer
Freshwater fish excrete diluted urine. This is a necessary adaptation to prevent water from entering their bodies osmotically, as they live in a hypotonic environment. The ammonia produced is excreted directly into the surrounding water, which is advantageous in terms of energy conservation.
Step 3
Urine concentration of Marine fish
Answer
Marine fish, similar to terrestrial mammals, produce concentrated urine. This adaptation reduces water loss in a hypertonic environment where they are at risk of dehydration. The marine fish also excrete urea as their nitrogenous waste, balancing their osmotic pressure with their environment.