READING PASSAGE 1
You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.
According to conservationists, populations of around two-thirds of butterfly species have declined in Britain over the past 40 years. If this trend continues, it might have unpredictable knock-on effects on other species in the ecosystem. Butterfly eggs develop into caterpillars, which consume vast quantities of plant material and serve as prey for birds, bats, and other small mammals. Understanding the reasons behind the decline in butterfly numbers is crucial if conservationists hope to halt or reverse the trend.
Butterflies prefer outdoor conditions that are “just right,” meaning neither too hot nor too cold. Under the conditions of climate change, temperatures in summer are generally getting warmer, leaving butterflies to adapt. One of the main ways species are adjusting is by altering the time of year they are active and reproduce. Scientists refer to the timing of these lifecycle events as “phenology.” When an animal or plant starts to do something earlier in the year than usual, it is said to be “advancing its phenology.”
These advances have been observed in a wide range of butterflies—indeed, most species are advancing their phenology to some extent. In Britain, as the average spring temperature has increased by roughly 0.5°C over the past 20 years, species have advanced their lifecycle by an average of three days to a week, aligning with cooler temperatures. Does this suggest that butterflies are well equipped to cope with climate change and can readily adjust? Or are they under stress, dragged along unwillingly by rapidly changing conditions? The answer remains unclear, but a new study aims to explore these questions.
Researchers began by compiling data from millions of records submitted by butterfly enthusiasts—people who spend their free time observing different species. This data provided information on 130 butterfly species in Great Britain over a 20-year period. Researchers then estimated the abundance and distribution of each species during this time, as well as how far north they had moved. The data also enabled researchers to estimate subtle changes in the timing of each species' transformation into an adult butterfly.
Analysing trends in these variables, the researchers found that species with more flexible lifecycles were better positioned to benefit from an earlier emergence driven by climate change. Some species can transform from caterpillar to butterfly two or more times per year, meaning the butterflies flying in spring are the grandchildren or great-grandchildren of those seen the previous year.
Among these species, those advancing their phenology the most over the 20-year study period also showed the most positive trends in abundance, distribution, and northward expansion. For species like Britain’s tiniest butterfly, the dainty Small Blue, this earlier development allows additional reproductive cycles by autumn, leading to population growth.
However, other species are less flexible, restricted to a single reproductive cycle per year. For these species, there was no evidence of any benefit to emerging earlier. Worryingly, the species in this group that specialize in very specific habitats, often tied to the caterpillar’s diet, tend to be most at risk from advancing phenology. The beautiful High Brown Fritillary, often described as Britain’s most endangered butterfly, belongs to this group. It is found only in coppiced woodland and limestone pavement habitats and is a single-generation butterfly that has advanced its phenology. This suggests that while climate change is not the sole cause, it may have contributed to the decline of this species.
All is not lost, however. Many of Britain’s single-generation species have the capacity, as seen in continental Europe, to add a second generation during sufficiently warm years. As the climate continues to warm, species like the Silver-studded Blue might be able to shift to multiple generations in the UK as well, potentially benefiting from the additional warmth and experiencing population increases.
In the short term, conservationists can use this knowledge to identify species that may be at risk. The White Admiral of southern England, a highly sought-after butterfly, saw a significant population increase from the 1920s but has experienced a sharp decline in the past 20 years. This may be due to the caterpillar’s sole reliance on honeysuckle as a food source, but climate change is also likely a contributing factor.
READING PASSAGE 2
You should spend about 20 minutes on Questions 14-26, which are based on Reading Passage 2 below.
Bacteria from the ocean floor can beat superbugs and cancer. But habitats are at risk from the hunger for marine minerals.
A
When Professor Mat Upton discovered that a microbe from a deep-sea sponge could kill pathogenic bugs in his laboratory, he realized it could be a breakthrough in combating antibiotic-resistant superbugs, responsible for thousands of deaths annually in the UK alone. Further tests confirmed that the antibiotic from this sponge bacteria, found more than 700 meters deep in the Rockall Trough of the northeast Atlantic, was previously unknown to science, increasing its potential as a life-saving medicine. However, Upton and other scientists who see the deep ocean as a prospecting ground for new medicines fear this potential may be lost as the rush to exploit deep-sea mineral resources gains momentum.
B
“We’re exploring the bioactive potential of marine resources to discover medicines or drugs before they are destroyed forever,” says Upton, a medical microbiologist at the University of Plymouth. He is among many scientists advocating for a halt to deep-sea mining to assess its pros and cons. “In terms of sustainability, this could be a better way to harness the economic potential of the deep sea,” he argues. Oceanographers using remotely operated vehicles have already discovered new species, such as sea cucumbers with tails enabling them to sail along the ocean floor and a rare ‘Dumbo’ octopus found 3,000 meters deep off the coast of California. Any of these species could offer life-saving potential. However, while it could take up to a decade for a newly discovered antibiotic to become a medicine, the race towards commercial mining in the deep ocean has already begun.
C
The deep sea holds more nickel, cobalt, and rare earth metals than all land reserves combined, according to the US Geological Survey. Mining corporations argue that deep-sea exploration could help diversify the supply of metals and highlight the growing demand for resources like copper, aluminum, and cobalt, used in electric car batteries and other technologies. They claim deep-sea mining could produce far superior ore compared to land mining with minimal waste. Most extraction methods involve adapting machinery previously used for terrestrial mining to excavate materials from the sea floor at depths of up to 6,000 meters. The extracted slurry, containing rock and solid particles, is brought to the surface, de-watered, and transferred for shipping, while the seawater is pumped back down near the seafloor.
D
Environmental and legal groups urge caution, warning of potentially massive and unknown environmental impacts and risks to nearby communities. They also argue that the global regulatory framework is not yet fully developed. A paper by Julie Hunter and Julian Aguon from Blue Ocean Law and Pradeep Singh from the Center for Marine Environmental Sciences in Bremen states that despite deep-sea mining being a recent development, it shares many characteristics with previous resource scrambles, including disregarding environmental and social consequences and marginalizing indigenous rights. The authors point out that knowledge of the deep seabed remains extremely limited. “The surfaces of the Moon, Mars, and even Venus have been mapped and studied in much greater detail than the deep sea,” the paper notes, stressing that marine scientists frequently acknowledge, “We don’t yet know what we need to know.”
E
Recent scientific research, including a study in Marine Policy, suggests that the deep seabed and hydrothermal vents, formed when seawater meets volcanic magma, play a crucial role in biodiversity and the global climate. The mineral-rich vents support diverse species, such as crustaceans, tubeworms, clams, slugs, anemones, and fish. The study warns that deep-sea mining poses a serious threat to these vital seabed functions. Extraction methods would create large sediment plumes and discharge waste back into the ocean, significantly disturbing seafloor environments. “On deep-sea vents, scientists are clear,” says Dr. Jon Copley of the National Oceanography Centre in Southampton: “We don’t want mining on them.”
F
The oceans cover about 70% of the planet and remain largely unexplored, says Mike Johnston, CEO of Nautilus, a Canadian underwater exploration company. “It makes sense to explore this untapped potential in an environmentally sustainable way, instead of continuing to deplete land resources to meet society’s needs,” he argues. Those driving the global push to deploy mining machines thousands of meters below the ocean’s surface claim that the environmental impacts will be much lower than on land. However, critics argue that these exotic and little-known ecosystems could be destroyed and must be protected. “Mining will be the greatest assault on deep-sea ecosystems ever inflicted by humans,” warns Verena Tunnicliffe, a hydrothermal vent expert at the University of Victoria in Canada. She advocates for strict controls and a ban on mining at active vents to preserve new knowledge and potential biotechnology benefits.
READING PASSAGE 3
You should spend about 20 minutes on Questions 27-40, which are based on Reading Passage 3 below.
A psychologist gives his view on how humans became self-centred
There has long been a general assumption that human beings are essentially selfish. We are often seen as ruthless, driven by strong impulses to compete for resources, power, and possessions. Even when we are kind, it’s often thought to be due to ulterior motives. If we are good, it’s supposedly because we’ve managed to overcome our innate selfishness and brutality.
This bleak view of human nature is closely associated with the science writer Richard Dawkins. His 1976 book The Selfish Gene became popular because it resonated with the competitive and individualistic mindset of late 20th-century societies. Like many others, Dawkins supports his views with evolutionary psychology, which suggests that present-day human traits evolved during the prehistoric period known as the "environment of evolutionary adaptedness."
Prehistory is typically seen as a time of intense competition when life was so harsh that only those with traits like selfishness, aggression, and ruthlessness survived. Since survival relied on access to resources such as rivers, forests, and animals, it’s argued that rival groups would inevitably come into conflict, leading to the development of traits like racism and warfare. This perspective seems logical, but it’s based on the incorrect assumption that prehistoric life was a constant struggle for survival.
It’s important to note that in prehistoric times, the world was very sparsely populated. Some estimates suggest that 15,000 years ago, Europe had a population of only 29,000, and the global population was less than half a million. These people were hunter-gatherers, living off wild animals and plants. With such low population densities, it seems unlikely that prehistoric groups needed to compete fiercely for resources or develop traits like ruthlessness and competitiveness, let alone engage in warfare.
There’s considerable evidence to support this idea from contemporary hunter-gatherer societies, which live similarly to prehistoric humans. Anthropologist Bruce Knauft has observed that hunter-gatherers are characterized by "extreme political and sexual egalitarianism." Individuals in these groups do not accumulate property or possessions and are ethically bound to share everything. They also have methods to maintain equality by preventing status differences.
For instance, the !Kung people of southern Africa exchange arrows before hunting. When an animal is killed, the credit goes not to the hunter, but to the owner of the arrow used. If someone becomes overly domineering, the group ostracizes them, expelling the offender from society. In such communities, men do not dictate women’s roles. Women in hunter-gatherer groups worldwide typically enjoy high levels of autonomy, choosing their marriage partners, deciding on their work, and determining their own schedules. In cases of divorce, women retain custody of their children.
Many anthropologists believe that societies like the !Kung were typical until a few thousand years ago when population growth led to the development of agriculture and settled communities. Given this context, it seems unlikely that traits like racism, warfare, and male domination would have been selected by evolution, as they would have had little advantage in the prehistoric era. Individuals who acted selfishly or ruthlessly would likely have been excluded from their groups, reducing their chances of survival.
It’s more logical, then, to view traits like cooperation, egalitarianism, altruism, and peacefulness as inherent to human beings. These traits dominated human life for tens of thousands of years and presumably remain strong in us today.
But if prehistoric life wasn’t as brutal as often assumed, why do modern humans behave so selfishly and ruthlessly? These negative traits might be a more recent development, triggered by environmental and psychological factors. Research consistently shows that primates like apes and gorillas become more violent and hierarchical when their natural habitats are disrupted.
The same phenomenon could have occurred with humans. I believe the shift from a hunter-gatherer lifestyle to farming coincided with a psychological change in some groups. A new sense of individuality and separateness emerged, leading to selfishness and, eventually, hierarchical societies, patriarchy, and warfare. These negative traits likely developed so recently that they cannot be fully explained through adaptive or evolutionary mechanisms.