By Washington Post, adapted by Newsela staff
The environment plays a role in the changing colors of leaves in autumn. Even as the leaves are dying, they are helping the trees prepare for winter. Photo from: Flickr.What is your favorite thing about fall? For many people, it is the changing leaves on the trees. In this season, the leaves change color. They turn from green to yellow, orange and red. Then the leaves change again. They turn brown. They get very dry. Finally, they fall to the ground. Then we can crunch them under our feet! Not all trees go through these changes. Only some have changing, falling leaves. Why do these leaves change color in the fall? Plants Need Sugar To GrowIn the spring and summer, leaves are green. This is because of chlorophyll. It sounds like CLORE-o-fill. It is a kind of pigment. A pigment gives something its color. Chlorophyll is a green pigment. It has a big job: It soaks up sunlight. Plants cannot eat the way people do. They make their own food. They do this through a process called photosynthesis. It is pronounced fo-toe-SYN-thuh-sis. Chlorophyl soaks up sunlight. The sunlight helps the plant turn air and water into sugar. That is the food plants need to grow. In fall, days get shorter. There is less sunlight. That means leaves cannot make as much sugar. Instead, they use sugar they saved up over the summer. So trees stop making chlorophyll. It would waste energy to make it. Before long, there is none left. All the green is gone. Red Leaves Live LongerThat explains where the green goes. Where do the new colors come from? Chlorophyll is not the only pigment in leaves. They have other pigments, too. They have the one that makes carrots orange. They also have the one that makes egg yolks yellow. Green steals the show for most of the year. After it is gone, the other colors show through. Then you see orange and yellow in leaves. Trees displaying their fall colors. In the fall season, the leaves change from green, to orange, red and yellow, and lastly to brown. Photo: Wikimedia Commons. Reds show up, too. They only show in the fall. Scientists are not sure why. Going from green to red takes a lot of sugar. That is energy trees should be saving up. One guess is that red protects dying leaves. This color blocks sun damage. It helps the leaves live longer. They can store more sugar for energy that way. So it may be worth it for the leaves to turn red. Not all trees turn the same colors. Some types of trees turn yellow. Others turn shades of yellow, orange and red. Crunchy Piles Of Brown LeavesFall begins with green leaves. They turn bright orange, yellow or red. But then they change again. Sunlight and frost kill off these pigments. Only one survives. It is called tannin. This pigment is brown. Next, the cells of the leaf break down. Leaves weaken and dry out. Wind shakes the branches. The dying leaves break away. Fall ends with crunchy piles of brown leaves. In spring, green will return. Trees will make new leaves. The color cycle will begin again. Respond to the below questions for the chance to earn extra credit! You will be entered into a raffle , the winners will be selected and posted on our blog page. 1. What do scientists believe leaves turn red? 2. What life characteristics is displayed when leaves change colors and eventually fall off? Explain.
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Newsela Article By Kevin Spear, Orlando Sentinel, adapted by Newsela staff 10/27/2017 Rachel Santulli works for Marine Turtle Research Group at Archie Carr National Wildlife Refuge in Brevard County, Florida. She monitors nighttime nesting of sea turtles, surveying hatching activity at daybreak. During an excavation, she found a live, baby green turtle. She released it and watched as it crawled into the Atlantic surf. Photo by: Kevin Spear/Orlando Sentinel/TNS. Beaches in Brevard County in Florida are a major refuge for sea turtles. Until last month, they were home to many nests. Then Hurricane Irma hit Florida. About half of all the green turtle nests were destroyed in the storm. Scientists called it a major blow to the threatened animals. But the big picture for green turtles looks much better. Scientist Kate Mansfield thinks Irma may just be a small setback. Mansfield works at the University of Central Florida, or UCF. She runs the school's Marine Turtle Research Group. In the 1980s, green turtles rarely appeared on Florida's Atlantic Ocean beaches. Over time, that changed. The number of green turtles grew larger and larger. It grew so large that it beat the number of loggerhead turtles this year.This trend is largely due to new laws. Some of the measures protect nests and eggs. Others help limit the use of bright lights that can disorient the turtles. Turtle Population Goes Down After HurricanesBut there's still one thing to worry about, Mansfield said. It's the number of damaging storms that continue to crash into Florida. "One year's storm is sad but not a big deal," said Simona Ceriani. She is a scientist with the Florida Fish and Wildlife Conservation Commission. "It's the frequency of storms that matters." Ceriani said green turtles were having great success before Irma. Unfortunately, the storm destroyed a lot of their progress. For more than 30 years, the UCF turtle group has been studying sea turtles. The scientists focus on the Archie Carr National Wildlife Refuge. This is a protected area. It stretches 20 miles along Brevard and Indian River counties. Many turtles give birth there. Their nesting makes up about one-third of all turtle nesting in the United States. This summer, the beach looked much different. Some parts of Archie Carr looked like they had been bombed. That's what happens when turtles plow up sand for thousands of nests. Mental Map Of The BeachUCF turtle scientists have made mental maps of the beach. They have learned how to read the jumble of holes and tracks. One of these scientists is Rachel Santulli. She said she is so familiar with the beach that she no longer uses her GPS to get around. Making sense of tracks and nests is best done in the evening, she said. That's because the sun is low and shadows are longer. It makes it easier to see turtle paths in the sand. For now, the sun was high in the sky. Santulli began digging through a nest where eggs had hatched.Her job was to record the number of empty shells. She also recorded the number of eggs that failed to hatch. There were nearly a dozen. Some were filled with a stinking liquid. Also deeply buried was a living, wiggling hatchling. Unlike its siblings, it wasn't able to tunnel out of the nest. "Nothing beats this," Santulli said as she carried the hatchling to the sea. "This is definitely one of the best parts." Comment one way you could help with this upsetting issue to be entered to receive extra credit. Get Creative! Winner will be announced on our blog feed!
![]() A GENIUS! The Great American Eclipse: This is a stellar couple’s costume option. On August 21, a solar eclipse passed over the United States, from Oregon to South Carolina. It was, unquestionably, one of the biggest events of the summer. This costume will be reusable: Another solar eclipse will pass through North America in 2024. ![]() 2. Nikola Tesla Grab a suit, draw on a mustache and strike the classic pose. One of the pillars of electrochemical science, Tesla is a perfect costume for science lovers across the board. You can even pull the whole costume together by talking to birds and telling them you love them. ![]() 3. Ms. Frizzle and the Magic School Bus A blue dress and some cut-out stickers. Dress up as your favorite cartoon school teacher from the 90's. Leave a comment of a Science Costume Idea on this blog to be entered to receive extra credit! Winner will be announced on our blog feed!
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