Secret of Staying Young Reading Answers: IELTS Reading Practice Test

The secret of staying young

A. The ant Pheidole dentata, which is native to the southeastern United States, is not immortal. According to scientists, it does not appear to show any signs of ageing. Old worker ants can do all jobs as well as their younger counterparts, and their minds appear to be just as sharp. According to Ysabel Giraldo, these ants do not appear to degrade. At Boston University, Ysable Giraldo's PhD dissertation was about ants.

B. Such feats of longevity are rare in the animal kingdom. Naked mole rats have a life expectancy of 30 years and are generally healthy throughout their lives. They can reproduce at any age and never get cancer. However, the majority of plants and fauna mature in the same way that humans do. Ants, like naked mole rats, are social insects that live in well-organised colonies. According to Giraldo, a researcher at the California Institute of Technology, P. dentata's social complexity makes it perfect for studying the ageing process in humans.

C. Pheidole dentata worker ants have a lifespan of about 140 days when kept in captivity. Giraldo studied four different age groups of ants: those between 20 and 22 days, 45 and 47 days, 95 and 97 days, and 120 and 122 days. Her research followed ants from the time they were just time the larvae developed into adults, so she knew how old they were for sure. They were then subjected to a battery of tests that she devised.

D. Giraldo observed the ants of a colony and made notes on how often each ant cared for, transported, and fed the colony's young. She examined the differences in ant foraging efficiency between ants aged 20 and 95 days by tracing the odours the insects leave behind as they eat food. She counted the number of times ants in a little dish crossed a line in order to determine how busy they were and to see how the ants reacted to light. She also conducted an experiment to see how ants would respond to a live prey item, in this case a fruit fly that was tethered. As Giraldo had predicted, the older ants were not going to fare well in any of these activities. Even the 95-day-old ants were able to follow the scent even further than their younger colleagues, proving that the senior insects were excellent caretakers and trail-followers. All of them were highly responsive to illumination, albeit the more active ones were the more senior ones. And when it came to responding to prey, the older ants attacked the hapless fruit fly with the same vigour as the juvenile ones, flaring their mandibles and yanking at the fly's legs.

E. Giraldo then examined the brains of 20-day-old and 95-day-old ants to look for dying cells. She found no significant differences in the location of dying cells with age, indicating that age did not appear to affect particular brain processes. Mushroom bodies are structures in ant and other insect brains that are necessary for information processing, learning, and memory. She was particularly curious about how ageing affects the density of synaptic complexes within these structures—regions where neurons converge. Once again, the response was unfavourable. Furthermore, neither serotonin or dopamine levels, which generally diminish with age, reduced in the old ants. In humans, a decrease in serotonin has been linked to Alzheimer's disease.

F. ‘This is the first time anyone has analysed behavioural and neurological changes in these ants in such detail," Giraldo says, whose findings were just published in the Proceedings of the Royal Society B. Senescence is the term used by biologists to describe age-related declines in bees; nevertheless, the results of current bee research have been conflicting; some studies have shown senescence, while others have not. "When asked about the mystery of P dentata's continued health, Giraldo states, "the investigation raises more questions than it answers for the time being."

G. Furthermore, if ants do not deteriorate with age, why do they die? Ants are unlikely to live for a full 140 days in the wild due to predators, illness, and a harsher environment than in the laboratory. "The fortunate ants that reach old age may experience a rapid decline shortly before passing away," Giraldo adds, though she is unsure because her study was not designed to track an ant's final moments.

H. Gene E. Robinson, an entomologist at the University of Illinois in Urbana-Champaign, emphasises that applying these findings to other species of social insects will be critical. This ant could be a one-of-a-kind creature, or it could represent a larger pattern among other social insects, providing insights into the science of ageing in larger species. In any event, it appears that age is unimportant to these ants.

Questions 1-8

The above reading passage has 8 paragraphs, A- H

Which paragraph contains the following information? Write the correct letter A- H in the boxes 1-8 on your answer sheet. 

NB You may use any letter more than once. 

Questions 9-13

Complete the summary below.

Choose NO MORE THAN THREE WORDS from the passage for each answer.

Write your answers in boxes 9-13 on your answer sheet.

Giraldo studied a colony of ants, focusing on their care for the 9. ___________, foraging efficiency, and responses to light and prey. She compared the behaviors of 20-day-old and 95-day-old ants by tracking their movements and responses to stimuli. Contrary to her expectations, the older ants excelled at following scents and were active caretakers, displaying similar aggression toward a10. ___________________as their younger counterparts.

Giraldo also investigated the brains of both age groups, searching for 11. _________________and assessing the density of 12. ___________________in mushroom bodies, which are crucial for learning and memory. She found no significant differences in dying cell locations with age and discovered that serotonin and dopamine levels did not decrease in older ants, suggesting that aging does not adversely impact specific brain functions in ants, unlike in humans where such declines are associated with 13._________________.