Osmoregulation and Excretion Flashcards
Osmoregulation balances the uptake and loss of
water and solutes.
An animal’s nitrogenous wastes reflect its
phylogeny and habitat
If the process of osmoregulation is based largely on the controlled movement of solutes between internal fluids and the external environment, then what’s the deal with water?
If water uptake is excessive, animal cells swell and burst; if water loss is substantial, they shrivel and die
What is osmosis?
How water enters and leaves cells- occurs when two solutions separated by a membrane differ in total solute concentration
What is osmolarity?
The unit of measurement for solute concentration- the number of moles of solute per liter of solution
If two solutions are separated by a selectively permeable membrane, what are isoosmotic, hyperosmotic, and hypoosmotic solutions?
iso- two solutions with the same osmolarity
hyper- when two solutions differ in osmolarity, the solution with the higher concentration of solutes
hypo- when two solutions differ in osmolarity, the solution that is more dilute
An animal can maintain water balance in
two ways.
What are osmocomformers? What kinds of animals are they?
animals that maintain water balance by being isoosmotic with its surrounding; marine animals
What are osmoregulators? What kinds of animals are they?
animals that maintain water balance internally indented of that of the external environment; freshwater and terrestrial animals
Most marine invertebrates are
osmoconformers
Many marine vertebrates and some marine invertebrates are
osmoregulators
Compared to the osmolarity of the surrounding water, what must the body fluids of most marine animals be?
isoosmotic
Freshwater animals have osmoregulatory problems that are opposite those of
marine animals.
Compared to the osmolarity of the surrounding water, what must the body fluids of freshwater animals be?
hyperosmotic
Salmon migrate between fresh water and seawater. How do they osmoregulate? What is it called when they adjust to different conditions?
when in freshwater they produce large amounts of dilute urine, when in ocean they produce only small concentrated urine and they excrete excess salt from their gills;
acclimatize
What is anhydrobiosis?
“life without water” animals enter a dormant state when their habitats dry up
What’s the deal with tardigrades?
tiny invertebrates less than 1mm long. In their active hydrated state they contain 85% water by weight; they can dehydrate to less than 2% water and survive in an inactive state, dry as dust, for a decade or more
What is trehalose?
a disaccharide used to protect cells by replacing the water that is normally associated with proteins and membrane lipids; a membrane protectant
Adaptations that reduce water loss are key to survival on land. What are some of these adaptations? How about body coverings? What about time of activity?
waxy layers of insect exoskeletons, the shells of land snails, and the layers of dead, keratinized skin cells covering most terrestrial vertebrates prevent dehydration; Some animals are nocturnal to prevent water loss;
How do animals lose water?
In urine and feces, across their skin, and from the surfaces of gas exchange organs
How do animals compensate for lost water?
Drinking and eating moist foods and by producing water metabolically through cellular respiration
How do animals maintain osmotic gradients?
Use active transport to manipulate solute concentrations in their body fluids
What does the energy cost of osmoregulation depend on?
how different an animal’s osmolarity is from its surroundings, how easily water and solutes can move across the animal’s surface, and how much work is required to pump solutes across the membrane
How do many animals minimize energy costs associated with osmoregulation?
by having body fluids that are adapted to the salinity of the animal’s habitat
