Natural selection is the process by which one type of animal within a species develops well because of certain characteristics that make it more likely to live than others in its group. The history of the peppered moth (桦尺蛾) is an example of the natural selection process.

In nineteenth-century England, certain types of peppered moths were able to better blend (融合) into their surroundings. During that time period, great changes were happening in Great Britain. The Industrial Revolution was part of this change, and with it came air pollution. Natural selection usually takes hundreds or even thousands of years to occur. For the peppered moth, this process occurred comparatively quickly.

At the beginning of the Industrial Age, most peppered moths in England were light-colored and covered with black markings, although a few moths had dark-colored wings. Because the light-colored moths blended into the light-colored bark on the trees, they could not be easily seen by birds that would eat them. As the air grew more polluted, however, tree trunks became covered with soot (煤烟) and became darker. The light-colored moths became easy for birds to see against the dark tree trunks. Since the dark-colored moths now had the advantage, their numbers grew. Within 50 years, the peppered moth went from being mostly light-colored to being mostly dark-colored.

In the twentieth century, the air cleared up, and the peppered moth population changed again. As tree trunks lightened due to less soot in the air, light-colored moths once again had an advantage. Their numbers increased as soot levels declined. Depending on their environment, the coloration of the moths helped them to be “naturally selected” to survive.

The North Star, also known as Polaris, is often used by campers to help them find their way when they get lost. 【小题1】 You can use them to find the North Star and help you if you lose your direction, or just find the North Star for fun if you’re into star gazing.

【小题2】 You can use the Big Dipper(北斗七星)to find the Little Dipper. The Little Dipper is the constellation(星座)that contains the North Star. The tip of the Little Dipper’s handle is the North Star. If you’re able to locate the Little Dipper, you can easily spot the North Star.

Locate the North Star with your smart phone. There are many smart phone applications that work something like a telescope. You allow the phone to find your location, and then point your phone to the sky. The phone acts as interactive map, identifying stars and constellations for you. 【小题3】

Buy a star atlas(星图). If the idea of carrying your phone around while stargazing kills the fun for you, consider buying a star atlas instead. You should also always take an atlas with you when hiking in case your phone battery dies. 【小题4】 A star atlas is a book that breaks down the night sky by the region and time of year. You can use it to locate the North Star on any given night.

【小题5】 You can use desktop applications for your computer to know how the sky will look on a given night. These devices can help you plan ahead. You’ll go outside with a rough idea of where you can expect to find the North Star.

Getting up early is actually the secret to the success of many people. 【小题1】

It may improve your cognitive (认知的) function.

People who get up early in the morning can concentrate better, are more attentive, and stay energized throughout the day.【小题2】 Therefore, focusing on important tasks earlier will allow you to make better decisions than people who work later. A 2010 Harvard University study found that morning people have better problem-solving skills, get better grades in school, and land higher-paying jobs.

It helps you sleep better.

Waking up early makes going to bed earlier easier and helps you get consistent sleep and wake time.【小题3】 Getting adequate sleep may lower your blood pressure, boost your mood, as well as improve your brain function. People who tend to be night owls are more likely to feel tired and develop sleep disorders.

It gives you more time to eat breakfast.

【小题4】 After all, food is the fuel people need to feel energized and ready to face the world. Just drinking a cup of coffee at the drive-through will not give you what you need. Enjoy a nutritious breakfast of health y bread rolls or yogurt and fruit to start your day off right.

It gives you more time for yourself.

Waking up early allows you to watch the sunrise and have quiet time at home. Self-care is vitally important, so take this time to enjoy your coffee, take your dog for a long walk, write your shopping list, or just take some extra me time. People generally think it is difficult to get more time for themselves.【小题5】