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
organisms who diffuse waste across body surfaces
- sponges
- cnidarians
- invertebrate excretory organ that developed from the ectoderm
- open to the exterior of organism
nephridia
- function like a kidney, removing waste materials through filtration
- closed
Flame cells
- propel waste matter down the tubules and out of the body through excretory pores that open on the body surface
- draw water from the interstitial fluid, allowing for filtration
cilia
Two architectural units of nephridia
- protonephridia
- metanephridia
- network of dead-end tubules without internal openings
- simple excretory structures found in flatworms
- occur both in coelomates and acoelomates
protonephridia
organisms with protonephridia
- Platyhelminthes (flatworms)
- Nemertea
- Rotifera
encloses protonephridia
flame cells
- prmitive excretory organs present in many invertebrates, originating in a ciliated coelomic funnel
- type of excretory glands with a ciliated funnel opening into the body cavity
- not enclosed by flame cells
metanephridia
organisms with metanephridia
- Annelids
- Arthropods
- Molluscs
where does metanephridia occur
coelomates
opening of the nephridia
- nephrostome
- nephridiopore
funnel-shaped opening of a nephridium into the body cavity
nephrostome
external opening of a nephridium, where waste is excreted from the cell
nephridiopore
- excretory and reproductive ducts found in some invertebrates that connect the coelom (body cavity) to the outside environment
- found in some mollusks
coelomoducts
where are coelomoducts found
some mollusks
- tubules connected to the digestive tract
- secrete nitrogenous easte
- found in terrestrial arthropods
- regulate water balance
malpighian tubules
where are malpighian tubules found
terrestrial arthropods
exits the malpighian tubules
uric acid and faeces
- glandular structures that remove waste products from the hemolymph
- found in crustaceans
green glands (antennal)
where are green glands found
crustaceans
parts of the anntenal gland (green gland)
- opening
- bladder
- tubule
- labyrinth
- end sac
- excretory organs near the base of legs that release waste through pores
- found in some arachnids
coxal glands
where are coxal glands found
some arachnids
organisms that maintain internal osmolarity similar to their environment
osmoconformers
e.g. of osmoconformers
- jellyfish
- sea stars
(many marine invertebrates)
organisms that actively regulate internal osmolarity regardless of external conditions
osmoregulators
e.g. of osmoregulators
- freshwater invertebrates
- terrestrial arthropods
organisms can tolerate only a relatively-narrow range of salinity.
Stenohaline
organisms are tolerant of a relatively-wide range of salinity
Euryhaline
- auxiliary organs of osmoregulation.
- By the absorption and excretion of ions, they support the limited potency of excretory organs to achieve homeostasis under extreme conditions of hydration and dehydration
- Chloride cells (ionocytes)
- salt glands
stenohaline organisms
osmoregulators
can be euryhaline organisms
osmoconformers
are those with higher salt concentrations than seawater
Hypersaline environments
organisms that thrive in Hypersaline environments
- brine shrimp (Artemia)
- other invertebrates
adaptations of organisms that thrive in Hypersaline environments
- efficient osmoregulation
- highly permeable membranes
- high hemolymph salt concentration
- cyst formation
take in water and excrete salts
highly permeable membranes
one mechanism to avoid water loss
high hemolymph salt concentration
- dormant form that can thrive for long periods of time
- highly resilient
cyst formation
have highly efficient osmoregulatory systems to minimize water loss
desert arthropods
example of desert arthropods
- scorpions
- certain ants
adaptations of organisms that live in the desert
- water conservation
- behavioral adaptation
- physiological adaptation
- water collection
water conservation of desert arthropods
uric acid waste
behavioral adaptation of desert arthropods
- nocturnal
- burrowers
physiological adaptation of desert arthropods
metabolic processes can tolerate high heat
water collection of desert arthropods
condensation of water on their body surface
- helps prevent loss of water
- impermeable, thick, waxy
exoskeleton
adaptations in this kind of environment include symbiotic relationships with bacteria and specialized excretory structures
hydrothermal vent
(high salinity, extreme temperatures)
what are the adaptations of organisms living in hydrothermal vents
- chemosynthetic symbiosis
- heat tolerance
- adaptations to toxic chemicals
- pressure adaptations
- aphotic conditions
uses chemicals to make food (bacteria)
chemosynthetic symbiosis
have heat shock proteins and other enzymes
heat tolerance (more than 100°C)
- evovled good mechanism to detoxify
- specialized gill structures
adaptations to toxic chemicals
detects infrared light
aphotic conditions
At depths greater than 200 m where light cannot penetrate
aphotic conditions
what do organisms detect in aphotic conditions
infrared lights
excretion in simple invertebrates
diffusion-based
excretion in higher taxa
more complex nephridial and tubular systems
there is a shift in __ and __ __ between terrestrial and aquatic invertebrates
- excretion
- osmoregulation strategies
enable invertebrates to thrive in varied environments
efficient waste removal and water balance