The discovery of Tiktaalik changed this thinking drastically. It is clearly a fish because it has scales and fins, but it is also clearly living in shallow water environments. How do we know this? Unlike its fishy contemporaries, Tiktaalik's body is extremely flattened. Its eyes are on the top of its head, suggesting it spent a lot of time on the bottom, looking up. Its shoulders are not connected to its skull, giving it a functional neck. And it has ribs exactly like those of its contemporary tetrapods which were used to support the body and aid in breathing.

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