Final answer:
Polar bears are struggling due to the melting of sea ice caused by global warming, which upsets the food web dynamics by creating competition on land and threatening their survival through loss of habitat and changes in biodiversity.
Step-by-step explanation:
Impact of Melting Sea Ice on Polar Bears and the Food Web
Because of global warming, polar bears (Ursus maritimus) are facing reduced feeding opportunities due to the melting of sea ice. They rely on sea ice as their primary hunting grounds to catch seals by waiting at breathing holes. As the ice melts, they must travel further, facing greater hazards to reach these hunting areas. If polar bears move to land in search of food, it will disrupt the balance of the local food web. As top predators, polar bears would compete with other land predators like grizzly and black bears, potentially edging them out but not gaining enough calories themselves. This competition could lead to a depletion of prey species and strain the ecosystem.
Polar bears maintain their body temperature in freezing conditions through adaptations such as thick fur and a dense layer of fat. These physical traits are essential for survival in their icy habitats, highlighting the significance of sea ice for their existence. The loss of habitat also leads to unexpected encounters and hybridization between polar bears and grizzly bears, as their ranges begin to overlap. The consequences of melting Arctic ice are not isolated to polar bears alone but influence a wide array of species, indicating a broader impact on biodiversity and ecosystem dynamics due to climate change.
Global warming, melting sea ice, and food web disruption are the focal concerns of the challenge polar bears face, underscoring the urgency to address climate change.