1 . After a five-year travel to study plants, animals and fossils (化石) in South America and on the islands in the Pacific, British naturalist Charles Darwin brought the idea of natural selection to the attention of the world in his best-selling book, On the Origin of Species.
Natural selection is the process through which populations of living organisms adapt and change naturally. Individuals in a population are naturally variable. In other words, they are all different in some ways. This variation means that some individuals have characteristics better suited to the environment than others. Individuals with adaptive characteristics — characteristics that give them some advantage-are more likely to survive and reproduce. These individuals then pass the adaptive characteristics on to their children. Over time, these characteristics become more common in the population. Through this process of natural selection, adaptive characteristics are passed on to the next generations. Those organisms that cannot adapt fast enough through natural selection will die out.
Natural selection can also lead to new and distinctly different species. It is one of the processes that drive phylogenesis and help to explain the diversity of life on Earth.
Darwin chose the name natural selection to contrast with artificial selection that is controlled by humans. Darwin and other scientists of his day argued that a process much like artificial selection happened in nature, without any human help. He argued that natural selection explained how a wide variety of life forms developed overtime from a single common ancestor.
Through studying the fossil record, we know that some species may not be able to adapt fast enough through natural selection and many of them that once lived on Earth are now extinct. Dinosaurs are one example. However, human actions such as over hunting and the destruction of habitats have become the main cause of extinctions today.
1. Why do some species die out according to the text?| A．They can’t adapt to the changed environments. |
| B．They fail to learn from their common ancestors. |
| C．They have too many variable individuals in the species. |
| D．They cannot find enough food and starve to death slowly. |
| A．Extinction. | B．Exposure. | C．Development. | D．Replacement. |
| A．Paragraph 1. | B．Paragraph 2. | C．Paragraph 3. | D．Paragraph 4. |
| A．Species’ extinction is slowing down recently. |
| B．Human actions can lead to species’ extinctions |
| C．Measures must be taken to stop eating animals. |
| D．Artificial selection is more important than natural selection. |
2 . New Holland honeyeaters are experts at sounding the alarm when there's danger, according to new research from biologists at the Australian National University (ANU) and the University f Cambridge.
Study authors, Dr Jessica McLachlan and Professor Rob Magrath, found honeyeaters can spread the word in the blink of an eye, using a two-stage alarm. It's particularly effective when they are threatened by fast-moving birds of prey. “When a hawk(鹰）is swooping down, its target has only a fraction of a second to flee to cover-a split second can make the difference between life and death," Dr McLachlan said. “But animals often signal urgent danger using repeated notes, which makes sure others hear the warning but it takes a long time to deliver.
“So there's a problem. How to send a lightning-fast message in a long call?” New Holland honeyeaters solve this problem elegantly. They “front-load” information about urgency into the first note of their alarm call, so other honeyeaters can respond quickly. The clever honeyeaters follow this up with more notes to intensify the message and signal how long to remain hidden. “They use a long call, with lots of notes, to make sure the message is heard,” Professor Magrath said. “And the more notes, the more urgent the danger. But they also modify the first note to indicate if it's necessary to take immediate cover. So it's a two-part message that is quick, reliable and informative.”
The technique is so effective that the authors expect to see other species adopt it. “Many other species modify alarm calls as the threat increases, but there is surprisingly little known about how fast they convey the message,” Professor Magrath said.
The researchers conducted their study in Canberra's Australian National Botanic Gardens over a period of several years. “These birds live in the Gardens and are used to having people around. This helped us to record natural interactions with their predators, such as sparrowhawks and currawongs (澳洲喜鹊),and to video the honeyeaters' responses to different alarm calls,” Professor Magrath said.
1. According to Dr Jessica McLachlan,________.| A．speed counts when it comes to honeyeaters' life or death |
| B．the second-part message in a honeyeater's call is more reliable |
| C．the message about where to take cover is conveyed very fast |
| D．the urgency degree relies on the first note in a honeyeater's call |
| A．The frequently repeated notes. |
| B．The relatively fixed amount of the notes. |
| C．The flexible adjustment of the notes. |
| D．A long-time delivery of the notes. |
| A．Objective. |
| B．Critical. |
| C．Appreciative. |
| D．Ambiguous. |
| A．the comparison between honeyeaters and other birds in botanic gardens |
| B．the analysis of length of alarm calls made by honeyeaters |
| C．the permanent account of the honeyeaters' response and signal transmission |
| D．the constant and systematic observation of birds in botanic gardens and beyond |
3 . Satellite imagery like Google Earth makes it easy for ecologists halfway around the world to check up on tropical forests—see illegal roads and logging (伐木), for example. But the information is limited.
“Satellite data often tells you what happens after it's happened.” Rhett Butler said, the founder of Mongabay. com, an environmental science news website. In a perspective piece in the journal Science, he and his colleagues write that sound recordings can supplement satellite data as another conservation tool.
You can actually set up alerts. So you can hear things like chainsaws (电锯) or gunshots in real time. So you can get put ahead of potential deforestation before it occurs. Small audio recorders, some of which are solar-powered and connecteded to cellphone grids for data upload, also give ecologists the ability to listen secretly on a jungle's biodiversity over time.
If you're in a primary forest, you'll tend to see all the frequencies of the soundscape occupied by different species. These are insects, birds, calling mammals, frogs things like that.”
As a comparison, here is a forest plot after selective logging---meaning some trees were cut, others left standing. “As you move into a more disturbed ecosystem, you'd start to see more gapsacross the frequencies of that soundscape.”
Certain insects dominate. And the diversity of calls declines as disturbance increases. While the human ear is perceptive (感知的), algorithms (运算法则) are a much more powerful tool to comb through thousands of hours of data, to get a richer picture of changing tropical biodiversity.
Nowadays, many industries---like cattle farming, palm oil, soybean and paper production are committing to zero deforestation goals, which can be hard to measure. But by coupling satellite data and camera traps with audio recordings, ecologists can keep their eyes-and ears-on what's going on in the jungle.
1. What is the disadvantage of satellite data according to Rhett Butler?| A．It carries little information. |
| B．It helps see illegal roads and logging. |
| C．It doesn't serve as a conservation tool. |
| D．It doesn't tell you until something has happened. |
| A．The majority of them are solar-powered. |
| B．they can update data everyday. |
| C．They enable ecologists to monitor the biodiversity in the jungle. |
| D．They allows you to hear things like chainsaws or gunshots after they occur. |
| A．Satellite imagery is used to check up on tropical forests. |
| B．A combination of Satellite imagery and sound recordings benefits forestation. |
| C．Many industries are committing to zero deforestation goals. |
| D．Sound recordings play an important role in preserving the forest. |
| A．Science | B．Sports |
| C．Finance | D．Entertainment |
