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With the completion of the Human Genome（基因组）Project more than 20 years ago, and the discovery of the double helix structure of DNA enjoying its 70th birthday last year, you might assume that we know how life works. Think again!

Evolution has a 4bn-year head start on us. However, several aspects of the standard picture of how life works-the idea of the genome as a blueprint, of genes as instructions for building an organism, of proteins as precisely tailored molecular（分子）machines and more-have wildly reduced the complexity of life. 

In the excellent book How Life Works, Philip Ball explorers the new biology, revealing life to be a far richer, more delicate affair than we have understood. Ball explains that life is a system of many levels-genes, proteins, cells, tissues, and body modules-each with its own rules and principles, so there is no unique place to look for an answer to it. 

Also, How Life Works is a much more appealing title than the overused question of "What is life?". We should be less concerned with what a thing is, and rather more focused on what a thing does. Defining a living thing implies an unchangeable ideal type, but this will run counter to the Darwinian principle that living things are four-dimensional, ever changing in time as well as space.

But it's an idea that is deeply rooted within our culture. Ball points out that we rely on metaphors（比喻）to explain and explore the complexities of life, but none suffice. We are taught that cells are machines, though no machine we have invented behaves like the simplest cell; that DNA is a code or a blueprint, though it is neither; that the brain is a computer, though no computer behaves like a brain at all.

Ball is a terrific writer, pumping out books on incredibly diverse subjects. There's a wealth of well-researched information in here, and some details that are a bit chewy for the lay reader. But the book serves as an essential introduction on our never-ending quest to understand life.

From wearing a lucky pair of socks to following family traditions, rituals (仪式) are embedded in our everyday lives. Rituals are central to actually all of our social institutions. They are held by the army, governments and companies, in parades or ceremonies. They are used by athletes who always wear the same socks for important games.

As we study rituals in a humanistic and scientific way, even if people perform those rituals without a clear purpose, or even when they do have a purpose, there is no particular causal (因果的) connection between the actions they take and that purpose. For example, when I perform a rain ritual, there is no connection between my movements and water falling from the sky.

But even so, just because ritual does not have any direct causal effect on the world, it does not mean that it has no effect on the world at all. In fact, rituals have very important functions in human societies. They help individuals through their anxieties；they help groups of people connect to one another；they help people find meaning in their lives.

In fact, even rituals that seem to be painful, stressful, or dangerous have measurable functions for people who perform them. For example, in the context of a fire walking ritual in Spain, we found that during this ritual, people's heart rates synchronized (同步). This was not just an effect of people moving at the same time—their heart rates would synchronize no matter what they were doing at the same time: walking on fire or just watching it.

What happened was that people started either adapting traditional ceremonies or creating new ceremonies. That's like what we saw when people in big cities came out on their balconies and started banging pots and pans together, in a show of solidarity (团结).

Recordings (录音) of angry bees are enough to send big, tough African elephants running away, a new study says. Beehives ( 蜂窝) either recorded or real may even prevent elephants from damaging farmer's crops.

Years ago, scientist Lucy King and her team found that elephants avoid certain trees with bees living in them. Today, Lucy wants to see if African honeybees might stop elephants from eating crops.

But before she asked farmers to set up beehives on their farms, she needed to find out if the bees would frighten elephants away.

Lucy found a wild beehive inside a tree in northern Kenya and set up a recorder. Then she threw a stone into the beehive, which burst into life. Lucy and her assistant hid in their car until the angry bees had calmed down. Next, Lucy searched out elephant families in Samburu National Reserve in northern Kenya and put a speaker in a tree close to each family.

From a distance, Lucy turned on the pre-recorded sound of angry bees while at the same time recording the elephants with a video camera. Half the elephant groups left the area within ten seconds. Out of a total of 17 groups, only one group didn't react to the sound of the angry bees. Lucy reported that all the young elephants immediately ran to their mothers to hide under them. When Lucy played the sound of a waterfall ( 瀑布) instead of the angry bees to many of the same elephant families, the animals were undisturbed. Even after four minutes, most of the groups stayed in one place.

Lucy is now studying whether the elephants will continue to avoid the sound of angry bees after hearing it several times. She hasn't tested enough groups yet to know and she has now begun placing speakers in the fields to see if elephants are frightened away.