The Importance of the Polar Bear's Y Chromosome

The well-known polar bear is one species that is particularly difficult to study it's evolution. This is due to the environment they live in and how it is hard to find their remains. Because of this, scientists have been studying their genes to fully understand their development. The Y chromosome has been studied extensively because of its ability to provide insights of genetic history. Using the Y chromosome gives access to unique information because it is only passed on to males. Their research concluded that there are two different male polar bear lineages across the world. This suggests that polar bears have roamed for many years and distributed their genetic information along the way. I found this article interesting because of how scientists found information on a species, despite the level of difficulty. Also, from this finding, the area of further investigation of polar bear development is endless.

The polar bear's genetic information is being used to study the development of the species.

Polar Bears Sunbathing All Summer Long

It has been a known fact that bears take to their caves with full bellies when the cold winter months come for a long sleep. However, what about those bears who thrive in the winter months living in a snowy environment? Polar bears were thought to enter a “walking hibernation” during the warm summer months to conserve energy and keep their body temperature at normal rates. Since food supply for these bears is much harder to come by when on land compared to seal hunting on the ice a form of “walking hibernation” seems to be an effective method. A biologist at the University of Wyoming, Dr. John P. Whiteman has been researching these creatures by inserting devices in a total of 10 polar bears found in the wild. These devices and collars were used to track the bear’s body temperature, the location, and the physical activity of the bears all during the summer months. The scientist has many more years of work ahead but his results so far show that polar bears are not taking any measures to reduce energy output or body temperature, which is what commonly happens when bears on the land hibernate. These polar bears in the summer months have been found to reuse chemicals within their bodies that is usually released as waste in order to help their bodies stay healthy during their fasting months. Also, the bears use the cold waters in order to cool their large bodies that are used to cold temperature.

The idea of a type of bear not hibernating is a strange thing to take it but many do not consider the fact that polar bears find the winter months to be ideal conditions. Polar bears are very different than other bears from their diet, environment, and colors making it understandable that they do not follow the same hibernation pattern or any pattern at all.

http://www.nytimes.com/2015/07/17/science/polar-bears-dont-go-into-hibernation-like-state-in-summer-researchers-say.html?action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=1&pgtype=sectionfront&_r=0

Female ancester of all living polar bears was a brown bear

According to an article from Biology News. Net, an international team of scientits has discovered that the female ancestor of all living polar bears was a brown bear that lived in the vicinity of present-day Britain and Ireland just prior to the peak of the last ice age -- 20,000 to 50,000 years ago. Beth Shapiro, the shaffer Associate Professor of Biology at Penn State Unibersity and one of the team's leaders, explained that climate changes affecting the North Atlantic ice sheet probably gave rise to periodic overlaps in bear habitats. These overlaps then led to hybridization, or interbreading -- and event that caused maternal DNA from brown bears to be introduced into polar bears.

Polar bears are being driven to extinxtion as increasing temperatures are devastating their habitat, melting away the Arctic ice the need to survive and causing the seals that polar bears hunt for food to become increasingly scarce. So a thorough understanding of the polar bear's deep genetic history and its response to previous environmental changes could help to inform conservation strategies for the dwindling polupation of polar bears today. Shapiro said that a more complete investigation of this part of the genetic story could answer deeper questions about how interactions with other species and environment changes affected the polar bear in the distant past, how frequently hybridizations between species actually happened, and how htese hybrizations affexted the genetic diversity of bear generally.