This is video is really aimed at kids but gives some good explanation of why it's likely impossible: https://youtu.be/YkS1U5lfSRw
The "gears" on this insect are basically intersecting teeth on two otherwise normal leg parts. Evolving an axle or any other free spinning part would require disconnected parts. The external parts would be cut off from any metabolic functions of the main body. Nothing remotely like that has ever evolved before so it would be nigh impossible.
The "gears" on this insect are basically intersecting teeth on two otherwise normal leg parts. Evolving an axle or any other free spinning part would require disconnected parts. The external parts would be cut off from any metabolic functions of the main body. Nothing remotely like that has ever evolved before so it would be nigh impossible.