Buzz
In 2014, Shi Ping Liu and colleagues conducted a study shedding light on this mystery. They compared the genetic makeup of polar bears with that of their closest relatives from warmer climates, brown bears. This comparison allowed them to identify genes that enable polar bears to thrive in one of Earth's harshest environments. Liu and colleagues discovered a gene called APoB, which lowers levels of low-density lipoproteins (LDLs) – a form of 'bad' cholesterol. In humans, mutations in this gene are linked to increased risk of heart disease. Therefore, polar bears may serve as a crucial model for understanding heart disease in humans.
The polar bear genome may also hold the key to another condition, particularly affecting older generations: osteoporosis. This disease, characterized by reduced bone density, is typically caused by lack of exercise, low calcium intake, or food scarcity. Bone tissue undergoes constant remodeling, with bones either gaining or losing mass depending on nutrient availability and stress levels. Female polar bears face extreme conditions during each pregnancy. In autumn, these females dig maternity dens in the snow and remain there throughout winter, before and after giving birth to their cubs. This period involves about six months of fasting, depleting their calcium and calorie reserves. Yet, their bones maintain robust density.
Physiologists Alanda Lennox and Allen Goodship unraveled this paradox in 2008. They found that pregnant bears can increase bone density before denning. Furthermore, when emerging with their cubs six months later, they show no significant loss in bone density. Hibernating brown bears lack this capability and must undergo extensive bone remodeling in the following spring. Understanding bone remodeling mechanisms in polar bears could potentially benefit many immobilized humans and even astronauts.
The significance of polar bears for human medicine is undoubtedly crucial in conservation efforts, yet this should not be the sole consideration. We often prioritize the protection of animals perceived as intelligent and emotional, like elephants and primates. Bears, however, are often viewed as less intelligent and sometimes aggressive. Nonetheless, field observations challenge these assumptions. For instance, a male bear named GoGo at Tennoji Zoo, Osaka, has been observed using tools to solve problems, such as using a tree branch to reach food. While such problem-solving skills are also observed in wild polar bears, they may not be as overt as with GoGo. Another example involves a male bear strategically leaping onto barrels in an attempt to reach a photographer standing four meters above.
Other studies, such as Alison Ames' 2008 research, reveal that polar bears exhibit deliberate and purposeful behavior. Ames documented instances of bears organizing objects into piles and then knocking them over, suggesting playful behavior and demonstrating their agility and calculated actions.
Regarding emotions, while the evidence remains anecdotal, many polar bears have been observed hitting ice and snow, seemingly out of frustration, when they miss a kill. Additionally, polar bears can form unique relationships with other species, including playing with sled dogs in the Arctic. Notably, a hand-raised polar bear named Agee has developed a close bond with her owner, Mark Dumas, even swimming together—an extraordinary relationship given that wild polar bears are known to actively hunt humans.
The potential extinction of polar bears due to climate change would mean not only losing opportunities for medical advancements but also the disappearance of a majestic and intelligent animal.
Questions 1-7
Are the statements following Reading Passage 1 accurate?
In boxes 1-7 on your answer sheet, write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
1 Polar bears suffer from various health problems due to the build-up of fat under their skin.
2 The study done by Liu and his colleagues compared different groups of polar bears.
3 Liu and colleagues were the first researchers to compare polar bears and brown bears genetically.
4 Polar bears are able to control their levels of ‘bad’ cholesterol by genetic means.
5 Female polar bears are able to survive for about six months without food.
6 It was found that the bones of female polar bears were very weak when they came out of their dens in spring.
7 The polar bear’s mechanism for increasing bone density could also be used by people one day.
Questions 8-13
Fill in the table below.
Choose ONE WORD ONLY from the passage for each answer.
Write your answers in boxes 8-13 on your answer sheet.
Reasons why polar bears should be protected
People think of bears as unintelligent and 8 ………………. .
However, this assumption may not hold true. For instance:
● In Tennoji Zoo, a bear has been seen using a branch as a 9 ………………. . This allowed him to knock down some 10 ………………. .
● A wild polar bear devised a strategy to access a platform where an 11 ………………. was situated.
● Polar bears have exhibited behaviors such as deliberate manipulation of objects and actions reminiscent of a 12 ………………. .
Bears may also express emotions. For instance:
● They may demonstrate movements indicating 13 ………………. when frustrated after a failed hunt.
● They can develop bonds with other species.
Responses
1 FALSE (Đoạn 1, “One reason for this is that they have up to 11 centimetres of fat underneath their skin. …Yet the polar bear experiences no such consequences.” → Gấu Bắc Cực không gặp vấn đề với lớp mỡ dày.)
2 FALSE (Đoạn 2, “Liu and his colleagues found the polar bears had a gene known as APoB, which reduces levels of low-density lipoproteins (LDLs) – a form of ‘bad’ cholesterol. In humans, mutations of this gene are associated with increased risk of heart disease.” → Các nhà khoa học bàn về các loại genes khác nhau của loài gấu chứ không phải các loài gấu khác nhau.)
3 NOT GIVEN (Không có thông tin về việc Liu và đồng sự có so sánh gấu Bắc Cực và gấu đen hay không)
4 TRUE (Đoạn 2, “Liu and his colleagues found the polar bears had a gene known as APoB, which reduces levels of low-density lipoproteins (LDLs) – a form of ‘bad’ cholesterol.”)
5 TRUE (Đoạn 3, “Once autumn comes around, … keep themselves and their cubs alive, depleting their own calcium and calorie reserves.” → Gấu Bắc Cực có cơ chế dự trữ năng lượng để sống sót qua mùa đông)
6 FALSE (Đoạn 4, “They discovered that pregnant bears were able to increase the density of their bones before they started to build their dens.” → Xương vẫn khoẻ, không bị yếu đi)
7 TRUE (Đoạn 4, “If the mechanism of bone remodelling in polar bears can be understood, many bedridden humans, and even astronauts, could potentially benefit.” → Có thể áp dụng cho người trong tương lai.)
8 violent (Đoạn 5, “Bears, on the other hand, seem to be perceived as stupid and in many cases violent.”)
9 tool (Đoạn 5, “A male bear called GoGo in Tennoji Zoo, Osaka, has even been observed making use of a tool to manipulate his environment.”)
10 meat (Đoạn 5, “The bear used a tree branch on multiple occasions to dislodge a piece of meat hung out of his reach.”)
11 photographer (Đoạn 5, “A calculated move by a male bear involved running and jumping onto barrels in an attempt to get to a photographer standing on a platform four metres high.”)
12 game (Đoạn 6, “For example, Ames observed bears putting objects in piles and then knocking them over in what appeared to be a game.”)
13 dismay (Section 7, “As for emotions, while the evidence is once again anecdotal, many bears have been seen to hit out at ice and snow – seemingly out of frustration…”)Practice for IELTS
