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Osmoregulation. Part 2. Monday. On Monday we covered 3 negative feedback loops that regulate water balance Today: we will cover some of the adaptations found in animals that live these environments Arid Wet Salt water/ marine Fresh water. Arid. Concentrated urine
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Osmoregulation Part 2
Monday • On Monday we covered 3 negative feedback loops that regulate water balance • Today: we will cover some of the adaptations found in animals that live these environments • Arid • Wet • Saltwater/ marine • Fresh water
Arid • Concentrated urine • Long loop of Henley= more water filtered out of urine • Urine is Hypertonic- it has more solutes (urea, uric acid, ammonia) than other body fluid of the animal Reptiles • Larger number of kidney tubules which can be inactive if dehydrated (filtering of blood is slower) • Ureta empties into the cloaca where more water is reabsorbed (this is reptile/bird speak for the anus) • Dry faeces • Storage of water in other ways- eg. Camels have a higher water content in their blood. • The problem in arid areas is how to conserve water and stay cool (sweating a lot is not the best response)
Wet • Osmoregulation in wet environments is not so problematic • BUT! • Single celled organisms will continue to absorb water via osmosis until they burst • UNLESS they have a contractile vacuole to expel excess water • Plants have cell walls to ensure that water absorbed stops
Marine • Fish- • urine is isotonic (same amount of solutes as body fluids) • Drink sea water and secrete salts through the gills • Only a small amount of urine produced • Birds • Water reabsorbed in the cloaca • Salt excreted via salt glands above the eye
Freshwater • Fish • urine is diluted= hypotonic • Don’t drink water • Frogs • Diluted urine in large quantities • Active transport of ions through the skin (to make up for those lost by diffusion) • Able to produce concentrated urine when conditions are dry
Now let’s look at some examples! • See activity