The table below lists different geographic regions inhabited by various bear species, arranged in order from the warmest to the coldest climate, along with the average adult body mass of each species:
ClimateGeographic Region (Bear Species)Average Adult Mass (kg)warmestSoutheast Asian Rainforest (Sun Bear)45\cline2−3↓Andean Cloud Forest (Spectacled Bear)110\cline2−3North American Temperate Forest (Black Bear)160\cline2−3Subarctic Yukon (Grizzly Bear)270\cline2−3coldestArctic Circle (Polar Bear)450\begin{array}{|c|l|c|} \hline \textbf{Climate} & \textbf{Geographic Region (Bear Species)} & \textbf{Average Adult Mass (kg)} \\ \hline \text{warmest} & \text{Southeast Asian Rainforest (Sun Bear)} & 45 \\ \cline{2-3} \downarrow & \text{Andean Cloud Forest (Spectacled Bear)} & 110 \\ \cline{2-3} & \text{North American Temperate Forest (Black Bear)} & 160 \\ \cline{2-3} & \text{Subarctic Yukon (Grizzly Bear)} & 270 \\ \cline{2-3} \text{coldest} & \text{Arctic Circle (Polar Bear)} & 450 \\ \hline \end{array}Climatewarmest\cline2−3↓\cline2−3\cline2−3\cline2−3coldestGeographic Region (Bear Species)Southeast Asian Rainforest (Sun Bear)Andean Cloud Forest (Spectacled Bear)North American Temperate Forest (Black Bear)Subarctic Yukon (Grizzly Bear)Arctic Circle (Polar Bear)Average Adult Mass (kg)45110160270450Use your understanding of natural selection and inheritance to suggest why the polar bears in the Arctic Circle have evolved the largest average body mass.
