Darwin's Theory: Variatio Evolution Of Polar Bears

The Polar bear lives in the artic and uses the area’s costal waters and ice sheets. They are well equipped to live in this environment because they have a thick coat which serves as an insulator. They mainly prey on seals but have also been known to consume dead whales. They can grow to be 7.25 to 8 feet tall and can weigh around 900 to 1,600 pounds. Polar bears are a keystone species, if their numbers decrease there is a possibility that the seal populations will increase which could be devastating for crustaceans and fish. They help keep populations in balance.

The bear have evolved along time ago and now there is only eight species existing. They evolved from early canids during the late Oligocene and early Miocene, about 25 million years ago. The earliest ancestors where the Dormaalocyon Latouri. An intermediate ancestor was the short faced bear, very similar to the modern day bear. It lived through the pleistocene period. It grew to thirteen feet long and was a herbivore. The ancestors to the modern day bears lived in the same climate and ate the same things. The modern bear contrast from the ancestor because the ancestor was more skinny and was smaller, and it was more cat like. The eight species of bear that still exist. They are the Polar bear, Brown bear, American black bear, Asian

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

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 a hump on their shoulders and a concave face. Their claws are 2-4 inches long, both their claws and humps are traits related to their great digging ability. (Basic Facts about Grizzly Bears) Grizzly Bear’s can be a variety of colors, from black to a very

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.

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.

Their feet are made for the ice and snow; they have rough leather pads so they don’t slip on ice, fur between toes and sharp claws as a weapon. They are plantigrade and left handed. Their toes are webbed so they can swim in water. Their fur is a yellowish white; the top lay is long and hollow to absorb heat and can float in the water. The undercoat covers their black skin that has four inches of blubber, which is an extra layer of warmth. This kind of coat makes it uncomfortable for polar bears to be in the heat. A polar bears sense of smell is the best sense they have, they mostly rely on it. It can smell a dead whale 15 miles away, can smell where a seal is hiding in six inches of ice, and can smell a human before they could even see them. Their eyes are small to block out the sun reflecting off the snow and their ears are small, close to their heads to keep warm.

Polar Bears have dens that tend to be 40 degrees warmer than outside. They has very thick blubber

The polar bear, the largest land carnivore in North America, one of the largest animals in the world and a favorite at zoos worldwide, has, over the years, adapted to its harsh Arctic environment. The appropriately named ‘ursus maritimum’ or sea bear usually lives between 15 and 18 years in the wild and spends most of its life on ice. It is the most recent of the eight bear species. The first polar bear was a brown bear subspecies, with brown bear dimensions and brown bear teeth. The polar bear evolution was rapid due to the small population and extreme pressure to survive. Even today, the polar bear continues to evolve to better adapt to the harsh realities of Arctic life.

Polar bears, whose scientific name is Ursus maritimus, is most commonly referred to as “sea bear” or “ice bear”. These bears are very interesting species that belong to the arctic region. In this essay, I will be discussing the polar bear’s behavior and the type of species interactions they have: The species interaction refers to symbiotic relationships. I will also be discussing a new research that may

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 polar bear lives up in the Arctic region where global warming and climate change are melting the ice caps that the bears thrive on. They use the ice as a platform from hunting and rest. The random pocket holes in the ice, where the seals pop up at, is where the polar bear catches its prey. With this reduction of ice, “the abundance of seals, and increases the amount of energy and time needed for hunting, leaving less energy for reproduction” (Endangered Species and Habitats).

 The polar bear has to be able to stay warm in the harsh winter cold. In fact sometimes because they have such thick fur they have to lay down on the snow to cool off so the harsh cold isnt even enough to keep them up to tempreture.

Male polar bears weigh about 350 to more than 650 kg and are about 2.5 to