Polar Bears

Ever wonder what animal can identify if salmon is male or female by taste? What bear is white but not albino? It’s the rare Kermode bear from the precious Great Bear rainforest located in British Columbia. With only 400-600 left, read on to learn why it is endangered and how we can help save this significant bear from extinction.

The Polar Bear (Ursus maritimus) is a bear native largely within the Arctic Circle encircling the Arctic Ocean, its surrounding seas and land masses. Although it is closely related to the Brown Bear, it has evolved to occupy a narrower ecological forte, with many body characteristics adapted for cold temperatures, for moving across snow, ice, and open water, and for hunting the seals which make up most of its diet. Though there are many theories surrounding evolution, the two stand outstanding hypotheses applying to the modification from Brown Bear to Polar Bear are Lamarck’s theory of Use and Disuse, and Darwin’s theory of Natural Selection. The intention of this paper is to compare these thesis and determine the most appropriate in

Anatomical Evidence – evidence relating to the structures of organisms and how they have evolved over time and might share a common ancestry.

Black bears in BC have a population that is 9 times that of the grizzlies, however, the results show that the grizzlies have inflicted 9.7 times more attacks on humans in the past 16 years. This goes to show that grizzly bears have a higher tendency to attack due to the natural factors and stresses that act on them cause them to be much more aggressive with less tolerance to threats (Herrero, Aspects of Evolution and Adaptation in American Black Bears (Ursus americanus Pallas) and Brown and Grizzly Bears (U. arctos Linne.) of North America n.d.). Many other papers such as Herrero’s study in both 1972 and 1985 showed the same results where grizzlies had higher rates of attacks compared to black bears in BC and so it clearly shows that there

Differences include the size of legs, ears, noses, paws, claws, jaws and the colour of the bear's fur. Polar bears generally have larger legs, smaller noses and ears, soft paws, short claws and small jaws with strong teeth. These adaptations have occurred to improve the polar bears wellbeing and chance of survival whilst living in the Arctic. Whereas, Brown bears have larger and more claws and a heavier and larger skull (Difference Between, 2014). This is too to help them survive in the environment.

Grizzly bears have had to adapt when the weather is off like having a warm winter it sets their internal clock off to where when they should be hibernating they are still out or cold weather comes late they are already awake from hibernation or cold weather comes to to early and they aren’t hibernating. They also have to deal with man made disasters like oil spills or fires, both can kill bears and kill what they eat like fish which could then kill the bears if they can not eat enough food because their immune system will deteriorate and kill them. Grizzly Bears are divergent because recent studies have shown that some grizzly bear’s mothers are polar bears and fathers are grizzly bears. This means that the fathers travel long distances to mate with mother polar bears. The most recent studies have suggested that they have been divergent from about 150,000 years ago. (Tia Ghose) Past research revealed that brown bears on ABC Islands, off the southeastern coast of Alaska, had mitochondrial DNA that look just like polar bear DNA.(Mitochondrial DNA comes only from the mother and is carried in the cytoplasm in the cell’s energy-making structures called mitochondria.) (Tia

The anglerfish and polar bear adapt to very extreme enviorments. The polar bears have to adapt to very  cold weather. The anglerfish have to adapt to the very  little food source they have in the deep sea. They both have devoloped many features that can help them while they live in these extreme enviroments.

In the scientific article, “Love in the Time of Climate Change: Grizzlies and Polar Bears Now Mating,” by Adam Popescu, believes that climate change is helping to cause grizzlies and polar bears to mate. He points out that glacier sheets are retreating, this forces the polar bears to move into grizzly’s territory. Moreover, that the permafrost is also starting to melt, which is causing grizzlies to wander into the polar bears territory. Consequently, he goes on to put that because of this mating, the grizzlies are eating up the polar bears genetically. He concludes that if this trend keeps up, in a few decades any kind of the bear population in this area will be no more. Lastly, the author’s purpose is to make readers aware of the hidden effects

White bears require a variety of physical characteristics to survive in the harsh environment of the Arctic. Large, wide paws with bumps allow them to distribute weight and grip more efficiently. Water resistant fur with a luminescent quality keep the bear warm and dry. Additionally, Sharp and powerful teeth have the ability to penetrate hard flesh. These special features allow not only the ability to thrive in a difficult environment, but also are important for communicating with other species and another bear.

It’s possible that the polar bear-like DNA actually comes from a living mammal—perhaps a brown bear—that happened to pick up a few mutations that created a false resemblance to that ancient polar bear DNA.

The American black bear lived during the same period as short-faced bears (Arctodus simus and A. pristinus) and the Florida spectacled bear (Tremarctos floridanus). These Tremarctine bears evolved from bears that had emigrated from Asia to North America 7–8 ma.[11] The short-faced bears are thought to have been heavily carnivorous and the Florida spectacled bear more herbivorous,[12] while the American black bears remained arboreal omnivores, like their Asian ancestors. The black bear's generalist behavior allowed it to exploit a wider variety of foods and has been given as a reason why, of these three genera, it alone survived climate and vegetative changes through the last ice age while the other more specialized North American predators became extinct. However, both Arctodus and Tremarctos had survived several other ice ages. After these prehistoric ursids became extinct during

began to adapt to a different life of cold weather and hunting seals. Brown bears originally are generalized and are capable of being able to live in a variety of habitats. Whereas polar bears are specialised to the environment and live on the edge of the Artic sea ice. They have discovered that it is known that polar bears split from brown bears between 300,000 to 400,000 years ago. A chemical analysis was taken place of a 120,000 year old fossil polar bear jawbone, this showed that in that time the species was already very dependent on marine prey which is rather different from a brown bears diet of a vegetarian fare. This then indicates that the genetic changes had only occurred in just a few hundred years. The jaw bone had provided the

It is suggested the split of the two species occurred between 600,000 and 5 million years ago but from researchers, a polar bear fossil was found which is dated to be about 110, 00 to 130,000 years old. After the split from the brown bears, the polar bear had to adapt and survive in the Arctic where they learn new skills to hunt seals and surviving in extremely cold weather. For the polar bears to be able to survive the cold, they were able to thrive on a fat- rich diet without apparent heart damage. The occurrence of the split between polar bears and brown bears was during a warm period where brown bears may have split their species to the northward and higher latitudes. When the colder climate returned, the polar bears had to be adapted to the new conditions. This affected the phenotype of the polar bears and brown bears but both species has similar

If the polar bear had to swim after their prey this would tire them out and they would most likely fail to catch their prey in order to consume it anyway. So the Ice caps are a polar bears hunting technique (BBC, 2014). Over the years scientists have found that there are around 19 populations of polar bear I four different ice regions throughout the artic. Polar bears have evolved over time and have adapted well to the extreme temperatures in the Artic unlike their land based ancestors (National geographic, 2014).Polar bears have particularly small ears to minimise heat loss, the smaller their ears are the less surface area there is (Endangered polar bear, 2013). Polar bears have also adapted to having a massive and extremely padded paws in order to protect them from the icy floors and a full, thick, fur coat; to protect them from the harsh weathers that living in the artic brings (polar bears international,

Comparative anatomy provides evidence for evolution because it illustrates the changes that have occurred over a large period of time. In the example, the feet/leg structure strongly provides evidence for evolution. This is because it is evident that the structure is changing slightly, this is most likely why there are two feet/leg structures for each fossil. The skull of is the most obvious piece of evidence and can vary