What do scientists think fish evolved from?

Scientists believe that fish evolved from lobe-finned fish that lived in shallow, freshwater environments about 400 million years ago.

Here's a breakdown of the key points:

* Lobe-finned fish are characterized by their fleshy, lobe-shaped fins, which were supported by bones. These fins allowed them to move across the bottom of shallow water and even crawl onto land.

* Tetrapods (animals with four limbs) are thought to have evolved from lobe-finned fish. The bones in the lobe fins are homologous (share a common ancestor) to the bones in the limbs of tetrapods.

* Tiktaalik, a fossil discovered in 2004, is considered a transitional species between fish and tetrapods. It had features of both, including scales, fins, and a primitive wrist.

* Evolutionary evidence supporting this theory comes from fossil records, comparative anatomy (comparing the structures of different species), and genetic studies.

While the exact path of fish evolution is still being studied, the link between lobe-finned fish and the ancestors of tetrapods is a well-supported hypothesis.