About Polar Bears; Polar Bears are marine mammals, that lives sea ice of the Arctic Ocean. Polar bears are the only bear that are classified as a marine mammal. They also have a thick layer of body fat that keeps them warm from the cold air and the freezing water.
Morphological and Molecular Evidence; Brown Bears from Alaska are the closest relatives to Polar Bears. Both bears have about a 6.5% similarity. Although the similarity percentage is very small, they both have similar body structures and systems.
Homologous Structures; Penguins and Brown bears have a very similar basic structure but a different functions. Brown bears and Polar bears are so alike because Polar bears evolved from Brown bears.
Vestigial Structures: For Polar bears, their vestigial structure is their whiskers. Vestigial structures is a structure in which the organism loses all of its original function. This happens in the course of evolution.
Transitional Fossils: Even though, Polar bears evolved from Brown bears, they aren't the same. For starters Brown bears are brown and Polar bears are white.
Comparative Embryology:
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