effects of water movement on cells without a cell wall:
lysis: when placed in a hypotonic medium, where the concentration of solutes outside the cell is lower than the concentration of solutes inside the cell, water moves into the cell by osmosis, to the point the cell bursts de to increased internal pressure
crenation: when placed in a hypertonic solution, where the concentration of solutes inside the cell is lower than the concentration of solutes outside the cell, water moves out of the cell by osmosis, to the point the cell shrinks due to the loss of water
--> potentially leads to cellular damage
evolution:
Amoeba and Paramecium have contractile vacuoles to prevent excessive water intake. Vacuoles actively expel water from the cell the maintain a correct intracellular solute concentration and prevent cellular bursting