The Effects of Global Warming on Polar Bears (Essay Sample)

The Effect of Global Warming on The Evolution of Polar Bears
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THE EFFECT OF GLOBAL WARMING ON THE EVOLUTION OF POLAR BEARS
Global warming and changes in climate have a significant impact on the life and evolution of polar bears. An analysis of the whole genome of polar bears provided important information on the evolution of species. This analysis shows that climate change and genetic exchange with brown bears led to the evolution of a new type of polar bear known today (Cahill, 2021). Genome analysis also suggests that the population of polar bears has reduced due to climate change. There is a possibility that the animals interbred with brown bears that became extinct millions of years ago. Global warming endangers the lives of polar bears forcing them to adopt survival mechanisms that have contributed to their evolution for ages (Cahill, 2021). The extinction of the brown bears and the emergence of the current breed is attributed to climate changes. As human activities continue depleting the ozone layer, climate changes contribute to reducing ice, which is the primary habitat for polar bears. As a result, many of these animals evolve ecologically, genetically, and physically due to changes in their habitat. It's essential to consider the factors that contribute to changes in feeding, movement, breeding, and adaptation of the polar bear to understand how global warming affects the evolution of bears.
Studies by Boonstra et al. (2020) found evidence that the polar bear population has fluctuated with crucial changes in climate over the past million years. The population increases during the cold seasons and reduces during the warmer times. This research further adds that although the polar bears evolved into a different species millions of years ago, these animals are likely to have interbred with brown bears until the recent past (about 150 000 years ago). This intimacy between the two species may result from climatic changes with the reduced glaciers, thus leading to the two species getting in closer contact as they share habitats. The interaction between the two species undoubtedly led to interbreeding, resulting in a new species of polar bears.
An analysis of the ABC brown bears' mitochondria sequences shows a semblance with that of the polar bears than with other brown bears. The semblance in the mitochondrial sequences indicates the possibility of other genomes similar to polar bears (Boonstra et al., 2020). The increased interbreeding between polar and brown bears led to an increased number of hybrids. These hybrids are a true example of the evolution of the modern polar bear. Changes in climate and glacier reduction created room for mingling and interbreeding, which led to the emergence of a new breed of polar bears. The intermingling of species is an important finding that emerged from data from studies conducted on the evolution of polar bears.
A notable difference in the genetic structure of polar bears enabled them to survive in the harsh climate of the arctic, eating different types of food and in a different environment (Rinker et al., 2019). Several studies discovered genes that may be the course of specific traits, such as changes in color (pigmentation) of the polar bear and the high-fat content of their milk. Researchers generated the first-rate set of data that included sequencing the entire genomes of the polar bears, including the three brown bears, a black bear, and a polar bear. Using small data segments, the researchers found out that polar bears are an older species than thought. Based on the DNA sequence, the split of the brown bears from polar bears happened 4.5 million years ago and not 600 years (Whiteman et al., 2018). These findings imply that polar bears persisted through warm periods. However, McKinney (2013) adds that species' endurance over many years does not guarantee their survival in the future. An increase in climate change might wipe the entire population of polar bears if their adaptation abilities decrease compared to the level of danger.
Scientists analyzed a deeply sequenced genome of the polar bears to model their historical populations. This analysis discovered the relationship between polar bears and the earth's climate history from their genes. The study helped to scientifically learn how climate affected polar bears and their role in their evolution. Through the study, scientists discovered that the population of polar bears increased at the end of the Early Pleistocene age when the earth became colder. There was a high reduction in the number of polar bears during the warmer times in the earth's history. This research also found that polar bears walk in smaller groups today compared to the prehistoric age. The loss of genetic diversity in modern polar bears makes them vulnerable and more sensitive to the threats posed by changes in the climate today. (Hamilton et al. 2019). From the research, it is possible to understand the differences between the past and present studies on the age of polar bears by examining the time of interbreeding between polar and brown bears since the species split from each other. Further analysis has led to the discovery that there are more similarities in the genetic composition of the polar bears and the ABC bears. This finding indicates that despite being different, these animals have exchanged genes through interbreeding since the time they separated and became different species. The findings indicate a possibility of polar bears mingling and interbreeding with others creating new species with distinct characteristics.
Distribution and Evolution of Bears
Bears have undergone different seasons of cooling and warming in the entire history of their evolution. In the last hundreds of years, they survived the interglacial periods where temperatures rose as high or higher than the present (Maduna et al., 2021). They also went through glacial periods where temperatures dropped, especially in the Northern Hemisphere. However, the continuous decrease of the sea ice and differentiation in sea ice breakup timing has dramatically affected the polar bear's distribution, ecology, and population. Variation in climate has influenced the distribution of polar bears since the end of the mid-Pleistocene period. However, lack of scarcity makes it hard to understand how the polar bears were distributed in the past. Remains found in London and Scandinavia show that polar bears moved further south during the glaciation period than they do nowadays.
There is essential information on the changes that happened during the last decade. Alaska, for example, has seen an increase in the number of polar bears from the Southern Beaufort Sea using the coastal habitats. Climate changes make the bears in this area move from the offshore ice to the environment near the shore in the autumn to look for seals. The autumn freeze-up has been delayed for between 1-2 months in this region during the last ten years. The frequency of interactions between polar bears in the landlocked area and people has increased. A similar distribution is also in the Northern Coast on Wrangel Island in the East Canadian and Russian arctics.
However, there are reports of decreased number of bears in the Baffin Bay due to overexploitation and unfavorable climate. The increased number of observations near the show reflects the changes in the distribution of polar bears. These changes are attributable to the reduction in sea ice and are not a sign of increased population. The study of the polar bears living in the western Hudson Bay in Canada shows that the climate changes have adversely affected the population (Malenfant et al., 2018). These changes in the Western Hudson Bay are an example of the effects of climate on other bears in the Arctic. The body mas of an adult female bear in Western Hudson Bay has dropped, thus affecting their reproduction (Malenfant et al., 2018). Delays in sea ice breakup increase the bears' weight, thus increasing their ability to raise children. The effects of global warming are in the differences between the reproduction of polar bears in the 80s and today.
The fecundity of female polar bears was high in the mid-80s compared to the current situation. During that time, females weaned almost half of their cubs at one and a half years instead of 2.5 years (Maduna et al., 2021). Environmental factors such as a change in climate contributed to the decline in the female's body condition, thus affecting their ability to conceive and wean offspring. The decrease in the population of male adults and females is attributed to factors including late freeze up and early breakup, reduction in snow, and unusual spring rainfall.
Effects of Global Warming
Global warming affects polar bears differently depending on the region and scenario. Direct effects of global warming include loss of sea habitat, whereas the indirect effects include the shift in prey availability and type. These changes affect geographic range and movement, reproduction, nutrition, and survival (Cahill et al., 2018). The quality of sea ice plays an essential role in the survival of polar bears and influences their life history and ecology. Insufficient sea ice leads to competition and forces the polar bears to come offshore and inhabit areas occupied by humans. Conflicts and struggles for self-defense create animosity between bears and humans, thus engendering the lives of the species. Studies by IUCN suggest that the continuous occurrence of ecological changes can make polar bears extinct. The reduction of ice cover is likely to cause a reduction of polar bears by more than 30%. It will also lead to decreased range of polar bears and uneven distribut...