You might think you have a great sense of smell, being able to identify what is cooking for dinner from upstairs! This is due to the process of diffusion. However, a dog’s sense of smell is up to 100,000 times stronger than ours. They can find a smelly sock amidst 2 million clean socks. Dogs have up to 300 million olfactory receptors, compared to only around 6 million in humans. Proportionally, the section of the brain responsible for analysing and processing smell is around 40 times greater than ours.
To help them with their amazing sense of smell, unlike us, when dogs exhale they send the air out through slits in the side of their noses. This means that new smells can go in immediately. Dogs have what is known as a Jacobson’s organ at the base of the nasal passage, used to detect pheromones(which are chemicals released by animals). In addition it can respond to large molecules, that don’t actually smell! This lets them know whether the opposite sex is available for breeding. It could also help a new born find it’s mum! Dogs can also wiggle their nostrils independently!!
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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