Evolution has its embarrassments. The laryngeal nerve developed its path underneath the aortic arch. In the giraffe it must pass all the way down into the chest and back again.
Yes, evolution is not designed by engineers. The giraffe is a rather awkward work-around based on the starting material. On the path of the laryngeal nerve, the comment might be, "well, we've always done it that way."
Got it. Your interestng comparative essay piqued my curiousity about other porpoise skeletal features and that's when I found the 3-D video. Now I know that they have only tiny remnants of the pelvic bone, among other cool adaptations. I have yet to jump into the bones of giraffes.
Walter, fascinating stuff! This 3-D video showing the skeletal assembly of a harbour porpoise helped visualize how other bones are specialized. https://www.youtube.com/watch?v=npyFvoiGM80 Heads to tails, the subject it's very interesting, indeed.
The video you linked to is excellent and beautiful, and way beyond my capacity to create. It would be great to have an animation of how the porpoise skeleton is modified from a more general mammalian skeleton. That's what I am trying to convey in my essay, using two extreme examples.
Walter- This was a very enjoyable read! Like some humans, do giraffes develop arthritis as they age? You didn’t mention cartilaginous cushions between vertebrae. I wondered if they wear out in the giraffe. Since that would seriously impede activities of daily living for those long-neck creatures, might there be some evolutionary modification which prevents that? Also loved the concept of “trade-offs” - life is a series of trade-offs some of which we choose and others choose us!!
Thanks, Nikki. The cartilages of the porpoise neck are very thin, and did not separate in death. That's in line with the neck's immobility. As for arthritis in giraffes, I don't know, but why not, if they live long enough in the wild?
Evolution has its embarrassments. The laryngeal nerve developed its path underneath the aortic arch. In the giraffe it must pass all the way down into the chest and back again.
EricJacobson
Yes, evolution is not designed by engineers. The giraffe is a rather awkward work-around based on the starting material. On the path of the laryngeal nerve, the comment might be, "well, we've always done it that way."
Got it. Your interestng comparative essay piqued my curiousity about other porpoise skeletal features and that's when I found the 3-D video. Now I know that they have only tiny remnants of the pelvic bone, among other cool adaptations. I have yet to jump into the bones of giraffes.
Walter, fascinating stuff! This 3-D video showing the skeletal assembly of a harbour porpoise helped visualize how other bones are specialized. https://www.youtube.com/watch?v=npyFvoiGM80 Heads to tails, the subject it's very interesting, indeed.
The video you linked to is excellent and beautiful, and way beyond my capacity to create. It would be great to have an animation of how the porpoise skeleton is modified from a more general mammalian skeleton. That's what I am trying to convey in my essay, using two extreme examples.
Wonderful examples of evolution.
Walter- This was a very enjoyable read! Like some humans, do giraffes develop arthritis as they age? You didn’t mention cartilaginous cushions between vertebrae. I wondered if they wear out in the giraffe. Since that would seriously impede activities of daily living for those long-neck creatures, might there be some evolutionary modification which prevents that? Also loved the concept of “trade-offs” - life is a series of trade-offs some of which we choose and others choose us!!
Thanks, Nikki. The cartilages of the porpoise neck are very thin, and did not separate in death. That's in line with the neck's immobility. As for arthritis in giraffes, I don't know, but why not, if they live long enough in the wild?