Answer:
What is an example of a freshwater
flatworm?
- An example of a freshwater flatworm is Planarian
worm. These flatworms belong to the class
Turbellaria.
- Planaria worms are found in both freshwater as well as
saltwater. These worms can also be found in most terrestrial
habitats.
What physiological problem must these animals solve when
living in that environment?
- Freshwater flatworms have the problem of absorbing excess water
from their surroundings. To overcome this problem, Planarian worms
contain protonephridia which is a specialized excretory system.
Protonephridia consists of dead end tubules and functions in
maintaining water balance.
- In freshwater Planarian worms protonephridia functions to
excrete the nitrogenous waste, diffusion of metabolic waste across
the body and helps in regulating the osmotic concentration
(osmoregulation).