Lasting genetic similarities make the two bears biological sister species, more closely related to one another than to any others. ... But Ursus maritimus has also evolved to match its polar environment, growing a longer snout than brown bears' and larger, paddle-like paws, both of which aid polar bears in hunting seals.
Two identical DNA strands
The reference point = a object used for comparison to determine if something is in motion.
An object is in motion if it changes position relative to a reference point.
You assume that the reference point is stationary, or not moving.
The answer is continental drift.
Continental drift is the geological theory that explains how continents move through Earth's surface. All continents were once connected as one supercontinent Pangea. On that supercontinent, many related species, such as llamas and camels, lived together on one location. But after continents spread apart, related species were separated on different continents and adapted to different conditions
