This class is believed to have evolved separately from the other three.

On Earth, eyes have evolved separately over forty times in different ways.

The stars have no major effect on each other, and essentially evolve separately.

They have evolved separately in belief and practices ever since.

But jazz evolved separately from tap dance to become a new form in its own right.

You said that our two races have evolved separately until now.

But we evolved separately, and if one world's idea is true, I suppose all must be.

"Anything that evolved separately from terran life would give itself away in an instant."

In each case the wings evolved separately, so their form reflects certain physical necessities.

Kenpo continued to evolve separately in both countries over the centuries.