Effects of Placing Fiddler Crabs in Distilled Water
What effect will placing a family of fiddler crabs from a saltwater aquarium into a container of distilled water have on the crabs?
The crabs are salt water organisms, so they'll have a higher concentration gradient than the distilled water. In other words, they're hypertonic to the distilled water. This will cause them to take on water and expand; their cells bursting.
Answer:
Since crabs are aquatic animals and thus when they are placed in freshwater, they do not get sufficient salt concentration to make themselves survive. The cells of the crab body (which was hypertonic in salt water) will now become hypotonic. Thus the osmo-regulation process will lower down thereby reducing the osmotic pressure as compared to the fluid outside. Also, the distilled water lacks basic nutrients required for the crab and its family to survive.
Explanation:
When fiddler crabs, which are saltwater organisms, are placed in distilled water, they face a serious issue of osmoregulation. As mentioned earlier, due to the higher concentration gradient of the crabs compared to distilled water, water will rush into their cells through a process called osmosis. This influx of water will cause the cells to swell and burst, ultimately leading to the death of the crabs.
Additionally, the lack of essential nutrients in distilled water will deprive the crabs of vital elements needed for their survival. Without these nutrients, the crabs and their family will struggle to maintain their biological functions and ultimately perish.