Unfortunately for slugs, their moist skin is far more permeable to water than the skin of most other animals. When salt is placed on them the process of osmosis begins quickly. The large amounts of water inside the slug move to the surface to try and restore equilibrium and dilute the concentration of salt. The unfortunate slug rapidly loses more fluid than it can tolerate, and quickly dies from dehydration. Luckily the same thing will not happen to us if we spill some salt on our skin! A slug contains much more water than we do and our skin is much more impermeable.
GCSE scientists – you need to be able to explain what osmosis is, and where it happens in living organisms. You also need to describe different ways substances can be transported, including diffusion and active transport. For help, try our “How to work with Diffusion, Osmosis and Active Transport” revision guide. It includes information on the different methods of transport. There are also questions for you to try, and answers to check your understanding.
Click on the picture below to see the guide:
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