Osmoregulation

Ocean

• 36 ppt salinity--stable
• Stenohaline organisms--narrow range of salinity
• Osmotic conformers--salt balance in organism matches environment

Osmoregulation

Estuary

• Changing salinity
• Euryhaline organisms--wide range of salinity
• Osmotic regualtors--internal salinity separate from external

Excretion ^(v)

• Excretion--digested food is absorbed and wastes are released as urine 

• Elimination--undigested food is released as feces

Excretion

Digestion of Proteins

• Amino acids break down
• Removal of nitrogen forms Ammonia--NH₃
• Ammonia can be converted to Uric acid or Urea 

Excretion

Nephridial organs

• Excretory structures
• Tubes open to outside
• Flatworms have protonephridia--end as flame cells
• Mollusks have metanephridia--open at both ends, surrounded by capillary bed

Osmoregualtion

FW Fishes

• Hypotonic--animal produces dilute urine
• Hypertonic--animal produces isotonic urine, drinks lots of water