chapter eight- smell that?

So this chapter was on the olfactory senses, and I have to say this was one of my favorite chapters because of how interesting it was. Again we can trace our sense of smell to more primitive organisms because it seems as though our olfactory senses are just multiples and copies of the more primitive genes. I was shocked about the fact that we as humans have many genes that deal with our smell senses (a whopping 3% of our DNA!!) but have been mutated so much they are rendered useless, yet we still have an amazing sense of smell. What I find most unbelievable is the fact that dolphins and whales have the same amount of olfactory genes as other mammels yet none of them function. For me, the question was not how but why? The blowhole where the olfactory senses are found is now only used for breathing and not smelling, and so therefore smell was not a necessity anymore and so the mutations were just passed down from generation to generation. I loved this chapter because of the idea that humans really made a trade-off when developing our senses; we traded more acute sense of smell for a more developed sense of sight, which was a more important development. Like Megan said, a good example would be dogs. Dogs see only in black and white yet can smell at such greater and more developed levels than most other animals, so therefore they made the trade down the line of evolution to focus on smelling rather than seeing. I loved this chapter because it was very to the point, I mean I understood the concept of how the olfactory senses work in one of the shortest chapters of the book with no questions! Shubin really amazes me with how he keeps me entertained while explaining difficult concepts at the same time.

By the way, the meat soup idea sounded amazing so I'm going to do it before the end of the summer :]