NEET BIOLOGY

Detailed explanation-1: -The ability for polar bears and grizzly bears to interbreed is unsurprising when you consider that polar bears evolved from brown bears as recently as 150, 000 years ago!

Detailed explanation-2: -Evolutionary studies suggest that polar bears evolved from brown bears during the ice ages. The oldest polar bear fossil, a jaw bone found in Svalbard, is dated at about 110, 000 to 130, 000 years old. DNA comparisons suggest the species may have split at least 150, 000 years ago, and maybe longer.

Detailed explanation-3: -The polar bear has evolved over time from the common brown bear by changing its fur colour to white, the ideal colour to blend in with its ice-covered surroundings. With new data an international research team now documents that the separation from the brown bear into an independent species has gone very quickly.

Detailed explanation-4: -Aside from their fur colors, the similarities are obvious. Both bears are powerful predators, with male polar bears growing as large as 1, 500 pounds, the same size as the world’s largest brown bear subspecies, the Kodiak bear.

Detailed explanation-5: -Bears are the youngest of the carnivore families, having arisen from doglike ancestors during the Eocene Epoch 55 million to 38 million years ago. The earliest bears had the characteristics of both dogs and bears, with heavy-set features and blunter teeth than those of true dogs.