Changes

Jump to navigation Jump to search
Line 17: Line 17:     
* Some organisms excrete nitrogen directly as ammonia
 
* Some organisms excrete nitrogen directly as ammonia
 +
* They are known as '''ammonotelic''' organisms
 
* This is how fish and aquatic amphibians excrete nitrogenous waste
 
* This is how fish and aquatic amphibians excrete nitrogenous waste
* Relatively toxic but it is better tolerated by aquatic animals
+
* Relatively toxic but it is better tolerated by aquatic animals due to dilution
 
* 400ml of water is also excreted per gram of ammonia making this an unrealistic option for terrestrial organisms
 
* 400ml of water is also excreted per gram of ammonia making this an unrealistic option for terrestrial organisms
 +
    
====Urea====
 
====Urea====
    
* Some animals process ammonia into urea  
 
* Some animals process ammonia into urea  
 +
* They are known as '''ureotelic''' organisms
 
* Mammals and terrestrial amphibians
 
* Mammals and terrestrial amphibians
 
* 40ml of water is excreted per gram of urea excreted
 
* 40ml of water is excreted per gram of urea excreted
 +
* Urea is very soluble and non-toxic
 +
    
====Uric Acid====
 
====Uric Acid====
* Referred to as Uricotelism
+
* Referred to as '''Uricotelism'''
 
* Urea is further processed to uric acid
 
* Urea is further processed to uric acid
 
* Carried out by birds and reptiles
 
* Carried out by birds and reptiles
 
* Only 8ml of water is co-excreted per gram
 
* Only 8ml of water is co-excreted per gram
* Highly insoluble
+
* Highly insoluble and less toxic than ammonia, though it can precipitate into body cavities
    
==Fish==
 
==Fish==
3,320

edits

Navigation menu