AP BIOLOGY ANIMAL NEWS It isn’t uncommon for the temperature to plunge down to -58 F (-50 C) during the winter. Most of the area averages around 20 inches of precipitation (mostly in the form of snow/ice), while parts of Greenland see around 47 inches of precipitation every year. There are about 1,700 different species of plants that live in the arctic tundra. These includes, flowering plants, herbs, mosses, grasses, small shrubs, and lichens (similar to fungi and algae). Other animals that live in the arctic tundra include the snowy owl, Canada lynx, tundra swan, arctic hare, arctic fox, beluga whale, caribou, narwhal, and seal. The biome does not experience many natural disasters. Blizzards are the most common natural disasters that occur. However, the arctic tundra has been facing problems and drastic weather changes as a result of global warming. The temperature has increased, the ice has been melting, and the plants and animals are seriously affected. The permafrost has continued to melt and thaw out. The melting of the permafrost releases more greenhouse gases, and many of the plants and animals are struggling to adapt to the drastic changes.
MAY 8, 2014 ! The polar bear resides along the coastal areas of northern North America, Greenland, and northeast Asia. Polar bears even live on moving masses of ice. The only density-dependent regulators that affect polar bears are global warming and competition for resources. Global warming has affected the number of living polar bears in the Arctic. It has melted many of the ice masses that were once homes to the polar bears, which has led to a decrease in polar bear population. This problem has grown significantly and has caught the attention of many nations and their citizens. Even though the polar bear is not at the top of the endangered species list, if the temperatures of the planet continue to go up, the polar bear population will drop even further. Additionally, competition for resources has increased amongst the polar bear population. Food can be scarce, from a lack of seals, to a lack of edible vegetation. There is a limited amount of food sources for polar bears in the Arctic Circle.
Polar Bears: Top of the Food Chain ! Male polar bears dominate a territory that includes the territories of multiple female polar bears. As an apex predator, the polar bear does not have any adaptations to defend itself from any natural predators. However, when males come in contact with one another, they often compete over mates with violent fighting. These fights can drag on for several weeks, and result in death or severe, long-lasting wounds for both bears. Females that refuse to mate with males may be attacked or abused. These female polar bears receive scratches and bite marks from mating refusals and from defending their cubs from violent males. Less often, orca whales have been known to kill and eat polar bears that are caught while swimming. Humans, while not a natural predator of polar bears, will occasionally hunt them as trophies. Despite a lack of natural predators on a higher trophic level, the polar bear population is shrinking. Even more threatening is the fact that genetic diversity amongst the diminishing polar bear population is dangerously low.
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