HomeMy WebLinkAboutRead Aloud Book Gr. 3-Lesson 16Have you ever seen pictures of a coral reef? If so, you know that a reef is
a rich environment where plants and animals live. This kind of environment is
an example of an ecosystem. When coral reefs are healthy, vegetation grows
thickly there. Many colorful fi sh swim in and around the plants. All this life
makes a coral reef a lush setting—but only when the reef is healthy.
Coral reefs are made from tiny animals called polyps. Coral polyps are like tiny
jellyfi sh. When the polyps become mature, or grown-up, they attach themselves
to a hard surface like a reef. The polyps then build tiny shells for themselves. A
large reef contains an abundance of shells—many millions of them. Coral reefs
come in many colors and form fascinating shapes. Some parts of a coral reef
look like human brains, while others resemble deer antlers or fans.
A coral reef is a very fragile environment. Many things can affect the reef
and the organisms that make the reef their home. For instance, if anyone
dumps chemicals into the water near a coral reef, or if other pollutants
appear, a series of changes may take place. Many plants and animals that
once fl ourished there would not be able to get the nutrients they need to stay
healthy. Then a coral reef is not such a beautiful place to visit.
Pollution changes the water, and sometimes the polyps die. Sometimes the
algae—tiny plants that live on the coral—die, too. Then the little animals that
eat the algae disappear. So do the bigger animals that eat the smaller animals.
Next, the coral changes color. Instead of being bright red, gold, or blue, it
becomes almost white. Scientists think that the world has lost as much as
one-third of its coral reefs from the effects of pollution and other human actions.
There are many different kinds of coral polyps. Scientists have collected
specimens to study how different chemicals and changes in water temperature
affect the polyps. The scientists hope that they can learn exactly what harms
the polyps and the other animals and plants that live in the reefs. Perhaps,
when we know what creates these problems, we can fi nd solutions. Then the
world will have beautiful, healthy coral reefs that are once again teeming with
all kinds of life.
COMPREHENSION What is one reason that animals in coral reefs might
die? How does a coral reef grow?
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Rachel wiped the sweat off her forehead. Her father, Chris, looked at her worriedly.
They had been hiking since eight o’clock that morning. Now it was late afternoon, and
Chris could see that Rachel was tired.
Rachel and Chris were climbing Mount Whitney, part of the sprawling Sierra
Nevada mountain range. The vast chain of mountains that made up the Sierra Nevada
stretched out across four hundred miles of land!
Rachel and Chris both loved being outdoors. Together, they had climbed many lofty
mountains that reached toward the sky. But Mount Whitney was special. The peak
of this towering mountain was the highest point in the United States. For Rachel and
Chris, the excitement of standing at the top of Mount Whitney would be stronger than
any thrill they had felt before. They just had to climb a little farther.
“Do you mind if we stop for a minute?” asked Rachel.
“Of course I don’t,” said Chris. The two hikers paused on the path and pulled their
water bottles out of their backpacks. They drank deeply from the cool, refreshing
water. While they drank, they rested their eyes on the sweeping views around them.
There was something beautiful to see in every direction.
From where they were standing, Rachel and Chris could see a string of peaks and
valleys extending across the sky from left to right. The highest mountaintops were
looming over the landscape like giants. Chris was almost six feet tall, but he felt tiny
compared to the huge mountain range. “It’s amazing,” Chris thought to himself. “A
mountain’s height is measured on a much greater scale than a person’s height!”
Rachel took a deep breath. The air along the trail was cool, and it smelled clean.
There were bear tracks in the dirt. Pine trees had needles of the brightest green. Rachel
loved being in the middle of a wide expanse of nature. It made her feel stronger.
Chris put his water bottle away and looked at his map. “The top of Mount Whitney
is only one hour away. Can you keep going?” he asked. Rachel nodded. Father and
daughter grinned at each other. Soon they would be looking out from the highest peak
in the country. Then all their hard work would be worth it!
COMPREHENSION What makes Rachel and Chris’s climb both diffi cult and
amazing? What words help you understand the size and height of the mountains
in the Sierra Nevada?
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