8 . The cultivation of plants by ants is more widespread than previously realized, and has evolved on at least 15 separate occasions.

There are more than 200 species of ant in the Americas that farm fungi (真菌) for food, but this trait evolved just once sometime between 45 million and 65 million years ago. Biologists regard the cultivation of fungi by ants as true agriculture appearing earlier than human agriculture because it meets four criteria: the ants plant the fungus, care for it, harvest it and depend on it for food.

By contrast, while thousands of ant species are known to have a wide variety of interdependent relationships with plants, none were regarded as true agriculture. But in 2016, Guillaume Chomicki and Susanne Renner at the University of Munich, Germany, discovered that an ant in Fungi cultivates several plants in a way that meets the four criteria for true agriculture.

The ants collect the seeds of the plants and place them in cracks in the bark of trees. As the plants grow, they form hollow structures called domain that the ants nest in. The ants defecate (排便) at designated absorptive places in these domain, providing nutrients for the plant. In return, as well as shelter, the plant provides food in the form of fruit juice.

This discovery prompted Chomicki and others to review the literature on ant-plant relationships to see if there are other examples of plant cultivation that have been overlooked. “They have never really been looked at in the framework of agriculture,” says Chomicki, who is now at the University of Sheffield in the UK. “It’s definitely widespread.”

The team identified 37 examples of tree-living ants that cultivate plants that grow on trees, known as epiphytes (附生植物). By looking at the family trees of the ant species, the team was able to determine on how many occasions plant cultivation evolved and roughly when. Fifteen is a conservative estimate, says Campbell. All the systems evolved relatively recently, around 1million to 3 million years ago, she says.

Whether the 37 examples of plant cultivation identified by the team count as true agriculture depends on the definitions used. Not all of the species get food from the plants, but they do rely on them for shelter, which is crucial for ants living in trees, says Campbell. So the team thinks the definition of true agriculture should include shelter as well as food.

9 . Reducing the workweek to four days could have a climate benefit. In addition to improving the well-being of workers, cutting working hours may reduce carbon emissions. But those benefits would depend on a number of factors, experts emphasize, including how people choose to spend nonworking time.

Commuting and travel

Transportation is the biggest contributor to greenhouse emissions. A November 2021 survey of 2,000 employees and 500 business leaders in the United Kingdom found that if all organizations introduced a four-day week, the reduced trips to work would decrease travel overall by more than 691 million miles a week.

But the climate benefits of less commuting could be eliminated, experts said, if people choose to spend their extra time off traveling, particularly if they do so by car or plane.

Energy usage

Shorter working hours could lead to reductions in energy usage, experts said. According to a 2006 paper, if the United States adopted European work standards, the country would consume about 20 percent less energy.

Energy could also be conserved if fewer resources are needed to heat and cool large office buildings, reducing demands on electricity. For example, if an entire workplace shuts down on the fifth day, that would help lower consumption — less so if the office stays open to accommodate employees taking different days off.

Lifestyle changes

It’s possible that fewer working hours may lead some people to have a larger carbon footprint, but experts say research suggests that most people are likely to shift toward more sustainable lifestyles.

One theory is that people who work more and have less free time tend to do things in more carbon-intensive ways, such as choosing faster modes of transportation or buying prepared foods. Convenience is often carbon-intensive and people tend to choose convenience when they're time-stressed. Meanwhile, some research suggests that those who work less are more likely to engage in traditionally low-carbon activities, such as spending time with family or sleeping.

“When we talk about the four-day workweek and the environment, we focus on the tangible, but actually, in a way, the biggest potential benefit here is in the intangible,” experts said.

10 . Montessori was born in Italy in 1870 with progressive parents, who frequently communicated with the country’s leading thinkers and scholars. This enlightened family environment provided Montessori with many advantages over other young girls of the time.

Her mother’s support was vital for some important decisions, such as her enrolment in a technical school after her elementary education. Her parents’ support also proved to be essential for her decision to study medicine, a field that was dominated by men.

Soon after graduating, in 1896, Montessori began work as a voluntary assistant in a clinic at the University of Rome, where she cared for children with learning difficulties. The rooms were bare, with just a few pieces of furniture. One day, she found that the children were enthusiastically playing with breadcrumbs (面包屑) that had dropped on the floor. It then occurred to her that the origin of some intellectual disabilities could be related with poverty. With the right learning materials, these and other young minds could be nurtured, Montessori concluded.

The observation would lead Montessori to develop a new method of education that focused on providing optimal stimulation during the sensitive periods of childhood.

At its centre was the principle that all the learning materials should be child-sized and designed to appeal to all the senses. In addition, each child should also be allowed to move and act freely, and use their creativity and problem-solving skills. Teachers took the role of guides, supporting the children without press or control.

Montessori opened her first Children’s House in 1907. When the Fascists (法西斯主义者) first came into power in Italy in 1922, they initially embraced her movement. But they soon came to oppose the emphasis on the children’s freedom of expression. Montessori’s values had always been about human respect, and the rights of children and women, but the Fascists wanted to use her work and her fame.

Things reached a breaking point when the Fascist tried to influence the schools’ educational content, and in 1934 Montessori and her son decided to leave Italy. She didn’t return to her homeland until 1947, and she continued to write about and develop her method until her death in 1952, at the age of 81.