Genetics is the key. Nose shape is supposed to be particularly “heritable” – which means that it is mostly defined by your DNA rather than by any other factors, so if you are looking for resemblance between family members, the nose is the best place to start. Other features can be more affected by the environment. This means, for example, that someone might have genes (i.e. functional bits of DNA) that code for very pale skin, but they live in a tropical climate so have permenantly sun-tanned skin. An interesting way of isolating environmental effects on appearance is by looking at identical twins – any differences between them must be due to the envronment since they have identical genes, as they came from the same embryo.
In a room full of 100 people they all look different; it is easy to distinguish one person from another. But in a field of 100 sheep, I could pick out the black one, but I would struggle to distinguish the other 99. But they cant all be genetically the same, there must be some differences between them. Are human able to tell humans apart much more easily that sheep?
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Chris commented on :
Yes Paddy, I blame my nose on my Mum and her Mum – it stands out for sure 🙂