1 . Humans evolved from apes. This is what we learned in biology class. But what came before apes? Chinese scientists have discovered fossils that could enrich the evolutionary story of how humans evolved from fish.
According to four articles published in the journal Nature in late September, Chinese researchers found fish fossils that provide the “missing link” about the origin of the jaw, a key feature that 99.8 percent of vertebrate (脊椎动物) species have.
Zhu Min, a lead researcher of the studies from the Chinese Academy of Sciences, said that the findings drew a large amount of interest in the science world due to the importance of jaws in animal evolution.
However, the rise of the jaw had been a mystery due to a lack of sufficient fossil evidence to support that jawed vertebrates lived 450 million years ago.
The latest findings made by Zhu’s team presented a set of five surprisingly well-preserved fish fossils that included three whole-bodied fish, helping scientists paint a more accurate evolutionary picture of the origin of the jaw. The fish fossils were discovered at two sites in Chongqing and Guizhou, whose strata (岩层) date back to the Silurian Period that began around 440 million years ago.
These fossils show that jawed fish were already thriving (繁荣) in the world’s ancient oceans at that time. Later on, more diverse and larger jawed fish evolved and began to spread around the world, paving the way for some fish to eventually go on land and evolve into other animals — including humans.
“These fossils provide an unprecedented (前所未有的) opportunity to peek into the ‘dawn of fish’ and help scientists trace many human body structures back to these ancient fish thus filling some key gaps in the evolutionary history of how fish evolved into humans,” Zhu said.
1. In which column of a magazine will you most probably read the passage?| A．Your Voice. | B．Animals. |
| C．Science Study. | D．History. |
| A．Because jaws are a key trait of all vertebrate species. |
| B．Because jaws are significant in animal evolution. |
| C．Because the rise of the jaw had been a mystery. |
| D．Because there is a lack of sufficient evidence. |
| A．Around 440 million years ago. |
| B．Around 450 million years ago. |
| C．When jawed fish began to spread around the world. |
| D．When fish evolved into humans. |
| A．Who Are Our Ancestors? | B．What Came Before Apes? |
| C．The Origin of the Jaw | D．Key Gaps in Evolution |
2 . In his first year at Harvard, Manny Medrano made a big breakthrough. With the help of his professor Gary Urton. Medrano interpreted a set of six khipus, knotted cora (打结的绳子)used for record keeping in the Inca Empire(印加帝国).
The Inca Empire reached the height of its power in 15th- and l6th-century Peru (秘鲁). When the Spanish arrived, the Inca had established the largest and most complex society in the Americas, but they left behind no written records. The only ones the Inca are known to have kept are in the form of khipus. In 2002, Urton began Harvard s Khipu Database Project. He traveled to museums around the world to record the numbers of knots, lengths of cords, colors of fibers, and other details about every Inca: khipu he could find.
Urton says he and other researchers in the field have always had a general sense of what the khipus represented. Many had to do with census(人口普查) data. Others appeared to be calendar systems. But, until recently, none of the khipus Urton studied could be understood on a very detailed level.
A turning point came when Urton began looking into a set of six khipus from the 17th-centurySanta River Valley region of Northwest Peru. One day, Urton picked up a book and happened to spot a Spanish census document from the same region and time period. “A lot of the numbers that were recorded in that census record matched those six khipus exactly, Urton says. Then he couldn't help mentioning it to his students. Medrano, who was among these students, asked if he could help during spring break.
Urton agreed to allow Medrano to look into the Santa Valley khipus and the Spanish census. Medrano recalls looking through spreadsheets in Microsoft Excel. He noticed that the way each cord was tied onto the khipu seemed to correspond to(符合, 对应) the social status (地位) of the 132 people recorded in the census document. The colors of the strings also appeared to be related to the people's first names. After spring break, Medrano told his professor about his theories. Medrano worked with Urton over the next several months and the two wrote a paper together.
1. Why did Urton travel to museums around the world?| A．To gather data for a project. |
| B．To learn how to make khipus. |
| C．To help Peru connect with the world. |
| D．To collect khipus as one of his hobbies. |
| A．Excited. | B．Puzzled. |
| C．Grateful. | D．Relieved. |
| A．Local people s first names came from Spanish |
| B．The colors of the strings tended to be the same. |
| C．How a cord was made differed in every period |
| D．How a cord was tied was related to one's social status |
| A．The Inca Empire had a long history. |
| B．The Inca Empire was a complex society. |
| C．A student assisted his professor in a technical paper. |
| D．A student uncovered the hidden secret of knotted cords. |
