Polar bear (Ursus maritimus) and brown bear (Ursus arctos) are recently diverged species that inhabit vastly differing habitats. … These results suggest that natural selection shaped patterns of CNV in response to the transition from an omnivorous to primarily carnivorous diet during polar bear evolution.
How does the environment affect polar bears?
Challenges affecting polar bears
The Arctic is warming about twice as fast as the global average, causing the ice that polar bears depend on to melt away. Loss of sea ice also threatens the bear’s main prey, seals, which need the ice to raise their young.
How does competition affect polar bears?
As more and more polar bears move onto land, competition for food will begin to increase. In addition, the likelihood of finding food along the coastline will probably be low as well. Thus, low food intake will likewise result in inadequate adipose stores.
How did polar bears evolve?
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.
What are 5 effects of climate change?
What are the effects of climate change and global warming?
- rising maximum temperatures.
- rising minimum temperatures.
- rising sea levels.
- higher ocean temperatures.
- an increase in heavy precipitation (heavy rain and hail)
- shrinking glaciers.
- thawing permafrost.
What are Darwin’s 5 points of natural selection?
In fact, it is so simple that it can be broken down into five basic steps, abbreviated here as VISTA: Variation, Inheritance, Selection, Time and Adaptation.
What selects against natural selection?
Natural selection only acts on the population’s heritable traits: selecting for beneficial alleles and, thus, increasing their frequency in the population, while selecting against deleterious alleles and, thereby, decreasing their frequency. This process is known as adaptive evolution.
Do polar bears eat fish?
Food Preferences & Resources
When other food is unavailable, polar bears will eat just about any animal they can get, including reindeer, small rodents, seabirds, waterfowl, fish, eggs, vegetation (including kelp), berries, and human garbage.
Do grizzly bears interact with polar bears?
In contrast, grizzly bears have not been observed using barrier islands; therefore, opportunities for polar bear–grizzly bear interactions or individual recognition are likely quite rare—except during sympatric use of the mainland or Drum Island.