16 펭귄의 구애에는 특별함이 있다

Reader's Bank_Level 7_Unit 06                                    Reading Text

Like humans, some animals give gifts to show their love. One example is the penguin. When a male penguin finds a female he likes, he shows his interest by offering her a pebble. Penguins use pebbles to make their nests. When the female takes the pebble, she places it in her nest. This means that she has accepted his proposal. The two penguins then stand together and perform a mating song. After this ceremony, the couple remains faithful to each other for life.

Pebbles play a significant role when penguins choose their mates. The size, shape, and smoothness of the pebble can show how strong the male penguin is. For this reason, male penguins search the beach thoroughly to find a smooth pebble. Sometimes, they dive into the water to find the perfect one. They even steal a pebble from a neighbor’s nest! Who knew that in the world of penguins, the perfect love story could begin with a pebble?

17 빛 공해, 자연의 길을 잃게 하다

Every year, millions of birds die because of city lights. The birds that migrate or hunt at night find their way by moonlight and starlight. When they reach big cities, they become confused by the bright lights. As a result, they crash into office buildings. On beaches near cities, baby sea turtles often crawl toward streetlights. The turtles mistake the bright lights for the moon. This causes them to get killed by passing cars. Some animals even have difficulty reproducing when they are exposed to bright city lights.

Studies show that too much light can also affect humans. When it is dark, the human body produces a hormone called melatonin. Melatonin helps improve immunity and block the growth of cancer cells. If people are exposed to too much light at night, they produce less melatonin. This can cause sleep problems and serious health issues.

Clearly, too much nighttime light is not just a problem for animals—it harms people too. Therefore, reducing nighttime light is essential for the safety of both animals and humans.

18 박테리아가 인류 최초의 조상?

A long, long time ago, the very first living thing on Earth was a tiny, tiny bacteria. It was so small that you couldn’t even see it! Over many, many years, this tiny bacteria changed and grew into all sorts of amazing creatures, like fish, lizards, animals with fur, and even people.

But how did this happen? It all started with the tiny bacteria fighting with each other. They tried to eat each other. One day, a big bacteria swallowed a small one. But the small bacteria didn’t want to be digested. So it offered a deal to the big one. It said, “Let me stay inside you, and I’ll help you in return.” The big bacteria agreed.

From that day on, they came to exist together. They stopped fighting and started working together to survive. The small bacteria became a special part of the big bacteria, like an organ. This special part is called a mitochondrion. *Mitochondria are like tiny powerhouses. They take food and turn it into energy for cells.

This way of bacteria living together led to the birth of many different living things. When only a few bacteria joined, they became small creatures. When many joined, they became bigger animals.