【推荐1】Consider the possibility that all human technology started with a mistake — or at least a lack of hand-eye coordination. In a new study published on Friday in Science Advances, Lydia Luncz and Tomos Proffitt, both at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, argue that mistakenly created flakes (薄片) may have been our ancient ancestors’ or other now-extinct early human relatives “first step toward creating the sharp-edged tools that they used to butcher animals and cut edible plants.

To do their research, Luncz and Proffitt traveled to an abandoned oil palm plantation near Thailand’s Phang Nga Bay and collected more than 1, 100 pieces of nut-cracking stones used by a troop of long-tailed macaques (猕猴). Macaques crack open oil palm nuts by placing them on a flat stone and striking their shell with another stone. These monkeys often miss the nut and accidentally break the stones, producing sharp flakes. Luncz and Proffitt analyzed these stones, which revealed a surprising fact: The flakes that the macaques unintentionally produced looked a lot like the oldest stone tools that were intentionally made by hominins (古人类).

Macaques don’t use the sharp flakes they create for anything, Luncz adds, noting that the monkeys have sharp teeth and don’t need cutting tools. The similar ancient stone tools collected from some of the earliest known sites, however, show evidence of being used for cutting tasks. For example, in Oldowan, a site dating between 3.3 million and 1.5 million years ago, researchers analyzed use-wear patterns on the tools and found that some of the flakes showed damage along their edges, indicating that they had been used for cutting. Cut marks on some fossils revealed that hominins had used stone tools for butchering the animals, making it clear that the sharp stone tools were anything but unintentional by-products of other pounding activities.

Despite the findings, to reveal the mechanism for the emergence of flake technology, researchers still need to learn how hominins made the leap from accidentally producing sharp flakes to picking them up and using them. Luncz and Proffitt hope to find the missing link in further studies.

【推荐2】Do you like to drink Coca-Cola? You can thank enslaved Africans. They brought the kola nut — one of the main parts of Coca-Cola — to what is now the United States. They also brought watermelon, black-eyed peas, some peppers and many more. These foods are eaten in the U.S. today. They show how Africans forced into slavery — beginning in the 1500s — influenced the American diet.

History professor Frederick Opie wrote a book about some of the foods that connect Africa and America—Soul Food from Africa to America. He says, “If you know what people eat, you can find out where they’re from.”

Opie explains that people who were bringing enslaved Africans to North America wanted to keep them alive and earn a profit. As a result, Africans on the slave ships were fed food they knew and liked. Those foods landed along with the people. Fruit and vegetables brought from Africa grew well in America. One reason is that enslaved Africans planted their own gardens to help feed themselves. In time, the plants from Africa slowly moved from gardens of the enslaved to those of the wealthy and powerful. For example, the homes of U.S. presidents George Washington and Thomas Jefferson had gardens planted with seeds from Africa.

Those fruit and vegetables changed the way cooks made foods in America. Take pies as an example. In England, pies were made with meat. African-Americans took the English meat pie and made it with fruit or vegetables, such as sweet potatoes. Yet for the most part, the skilled black chefs have been written out of American history. In fact, both their work and their skill shaped American food. Some ways of cooking that are well-known in the U.S. today were reported in West Africa before 1500. They include deep frying fish and barbecuing meats.

【推荐3】Mont Kilimaniaro is among Africa’s most breathtaking sites, but hard times have come to the plains below. Death is all around and it’s tragic to behold. The cause is a lack of rainfall in a land where on the contrary there is still plenty of water. Underground springs fed by snowmelt from the mountain, still create swamps(沼泽). The problem is that the absence of rain means grasses and other essential plants are not growing, and the animals that depend on them are dying from a lack of nutrition.

The elephant herds here are among the most successful in the continent. They’re closely monitored and conservationists have given them names. But even these great beasts are dying too, what is for the smaller ones?

A drought induced hunger. Since the start of June almost 60 elephant deaths have been recorded. More than half calves were killed by starvation due to their mothers’ failure to produce milk. Tolstoy, a male, was named after Russian. He was 5-year-old at the time of his death. And he was one of the greatest tuskers like one of the greatest alive.

Very sad story. There are some of the last relatively undisturbed elephants in Africa. While poaching(偷猎)has been destructive elsewhere，these animals have been largely spared. Right now, however, the problem they face here is a drier climate which poses the greatest threat to their survival.

There are plenty of people here who care deeply about these elephants, but the sad truth is that conservationists are powerless to stop the dying. Only fresh rainfall and new plant growth can do that. We are waiting for the rains. If the rains don’t come before the end of the year, the death rate will only increase.