lecture 08 - resource constraint: water

Question 1

why does the heat not kill you?

Answer 1

dehydration does

Question 2

water = life?

Answer 2

essential to organisms as most are comprised of 50-90% water
must maintain internal concentrations of substances like salts to survive

Question 3

ppt

Answer 3

parts per thousand unit for concentrations

Question 4

freshwater ppt

Answer 4

5 ppt

Question 5

estuaries ppt (brackish environment)

Answer 5

10-25 ppt

Question 6

oceans ppt

Answer 6

35 ppt

Question 7

what accounts for salinity in bodies of water?

Answer 7

sodium or sulfates

Question 8

diffusion

Answer 8

movement of soluble salts or water due to random movement of particles (salt concentrations are equalized in a solution)

Question 9

osmosis

Answer 9

movement through a semipermeable membrane, such as a phospholipid cell membrane (it is permeable only to some molecules, such as water)

Question 10

osmolarity

Answer 10

refers to the amount of solute/water in a solution in relation to a reference (its environment)

Question 11

hypoosmotic

Answer 11

low solute concentration, high water concentration
organism has higher water concentration and lower solute concentration than the environment

Question 12

hypersmotic

Answer 12

high solute concentration, low water concentration
organism has lower water concentration and higher solute concentration and solutes as the environment

Question 13

isosmotic

Answer 13

same solute and water concentration
organism has the same water concentration and solutes as the environment

Question 14

hypoosmotic marine organisms

Answer 14

low osmotic pressure in blood
risk dehydration and surplus intake through gills

Question 15

solutions to hypoosmotic marine organisms

Answer 15

drink constantly to counteract dehydration
low urination rates and volumes
get rid of excess salt through specialized chloride cells in the gills (adaptation)

Question 16

isosmotic marine organisms

Answer 16

internal body concentrations of salts and water are equivalent to the concentration in their external environment

Question 17

hyperosmotic marine organisms

Answer 17

risk too much water entering the organism and too many salts leaving the organism

Question 18

solutions to hyperosmotic marine organisms

Answer 18

do not drink
excrete excess internal water via large amounts of dilute urine
replace salts by absorbing sodium chloride in gills and by ingesting food

Question 19

fish that move between salt and fresh water

Answer 19

acclimate to salinity of their new environment (reversible physiological change)

Question 20

anadromous

Answer 20

born in freshwater, spends most of its life in the sea, and returns to freshwater to spawn

Question 21

catadromous

Answer 21

born in the ocean, spends most of its life in freshwater, and returns to the ocean to spawn

Question 22

water potential

Answer 22

water moves from high to low water potential, if there are differences in water potential, water will move

Question 23

where is the lowest water potential in plants

Answer 23

tree canopy/tree trunk

Question 24

why is the lowest water potential in the canopy and trunk

Answer 24

leaf surface interfaces with the air causing evaporation and transpiration

Question 25

water acquisition in terrestrial plants

Answer 25

acquisition of water in roots is essential for the water pump to work but water is limited in many environments

Question 26

what is the root adaptation for plants in dryer climates

Answer 26

roots grow deeper into the soil to acquire water found in deeper soil layers or at the groundwater level

Question 27

water acquisition in terrestrial animals

Answer 27

drinking food and water

Question 28

water conservation in terrestrial animals

Answer 28

think waxy cuticles to avoid water loss
protective and waxy or hard layer covering the epidermis of a plant, invertebrate or shell

storing water when it’s available and releasing it slowly in period of drought

conservation of urine, feces and sweat to minimize water loss

behavioural adaptations to minimize water loss

Question 29

water conservation in terrestrial plants

Answer 29

wilting as a strategy to reduce water loss