Lesson 4 - Excretion and Osmoregulation Flashcards
elimination of metabolic waste products from the body
excretion
regulation of water and ion balance within the body fluids
osmoregulation
Different types of organisms with different excretion
- ammonotelic
- ureotelic
- uricotelic
- guanotelic
- excreting ammonia as the main nitrogenous waste
- do not need energy, but requires a lot of water
- from protein
ammonotelic
example of ammonotelic organisms
- protozoans
- crustaceans
- platyhelminths
what do ammonotelics excrete
ammonia
- term used to describe animals that excrete most of their nitrogen waste products as urea
- found mostly in terrestrial organisms
- needs energy
ureotelic
less toxic form of ammonia
urine
what do ureotelics excrete
urea
example of invertebrate ureotelic
earthworm
- cells in annelids that function similarly to the liver in vertebrates
- The cells store glycogen and neutralize toxins.
- converts ammonia to urea
Chloragogen cells
- excrete uric acid or its salts
- Because uric acid is less toxic and more water soluble than ammonia and urea, it can more easily be stored in the body and requires less water for excretion.
- organisms live in arid environments
uricotelic
what do uricotelic excrete
uric acid
example of uricotelics
- terrestrial insects
- reptiles
- birds
description of uric acid
pasty consistency, crystalizes
advantage of uric acid
can be stored in the body for an indefinite period
weight of uric acid
can take as much as 10% in their dry weight
- Animals that excrete guanine as their waste product
- less water
- more energy
- intermediate metabolite of uric acid
guanotelic
what do guanotelics excrete
guanine
guanine is an intermediate metabolite of what
uric acid
advantages:
ammonia
produced with little energy
advantages:
urea
- less toxic than ammonia
- less water needed to excrete
advantages:
uric acid
very little water is excreted with it
advantages:
guanine
- relatively non-toxic
- less water is excreted
disadvantages:
ammonia
- toxic in concentrated solution
- must be excreted in a lot of water
disadvantages:
urea
require little more energy to produce it
disadvantages:
uric acid
requires considerable energy to produce it
disadvantages:
guanine
more energy needed
habitat:
ammonia
water
habitat:
urea
- land
- sea
habitat:
uric acid
land
habitat:
guanine
arid habitat (land)
excreted by:
ammonia
- marine and freshwater invertebrates
- bony fish
- amphibian larvae
- crocodiles
excreted by:
urea
- adult amphibians
- turtles
- mammals
- bony fishes
excreted by:
uric acid
- reptiles
- birds
- insects
- land gastropods
excreted by:
guanine
- scorpions
- spiders
Different Excretory Mechanisms
- diffusion across body surfaces
- nephridia
- coelomoducts
- malphigian tubes
- green glands (antennal)
- coxal glands
simple diffusion of wastes in organisms like sponges and cnidarians
diffusion across body surfaces