Robert Clarkのインスタグラム(robertclarkphoto) - 8月6日 04時39分

This is the ear bone of a whale, I shot this picture while working on the evolution of Whales story for @ナショナルジオグラフィック. The size and shape are very similar to human and our other relatives.

The evolution of mammalian auditory ossicles is one of the most well-documented and important evolutionary events, transitional forms as well as an excellent example of adaptation, the re-purposing of existing structures during evolution.

Over the course of the evolution of mammals, one lower and one upper jaw bone lost their purpose in the jaw joint and were put to new use in the middle ear.
The mammalian middle ear contains three tiny bones known as the ossicles: malleus, incus, and stapes (hammer, anvil, and stirrup respectively). The ossicles (all three bones) are a complex system of levers whose functions include: reducing the amplitude of the vibrations; increasing the mechanical force of vibrations; and thus improving the efficient transmission of sound energy from the eardrum to the inner ear structures. The details of these structures and their effects vary noticeably between different mammal species, even when the species are as closely related as humans and chimpanzees.#EvidenceofEvolution #Evolution #whales @Robert Clark @thephotosociety @instituteartist

[BIHAKUEN]UVシールド(UVShield)

>> 飲む日焼け止め！「UVシールド」を購入する

• ナショナルジオグラフィック