Yes.
While the fall foliage in North America and East Asia takes on a fiery red hue, perplexingly, autumn leaves in Europe are mostly yellow in color. A team of researchers has a new idea as to why the autumnal colors differ between the continents, one that involved taking a step back 35 million years in time.
The green color of leaves during the spring and summer is a result of the presence of the pigment chlorophyll, which allows plants to capture sunlight and produce energy by the process of photosynthesis.
When the weather begins to turn cool in the fall, chlorophyll, which is sensitive to the cold, stops being produced. As the green fades, yellow and orange pigments called carotenoids (also responsible for the orange color of carrots) take over. These pigments were always present in the background of the leaves' color, but can finally shine through as the green diminishes.
While this process has long been known to scientists, the mechanism that results in red hues has proved trickier to understand, particularly because of the energy the tree must use to produce them at a time when the leaves are about to die anyway.
The red color comes from anthocyanins, which unlike carotenoids are produced only in the fall. These red pigments act as sunscreen for the trees by blocking out harmful radiation and preventing overexposure to light. They also act as an antifreeze, preventing leaf cells from freezing easily in the autumn chill.
Some scientists have even suggested that the red colors ward off pests that would munch on the leaves if they were a more appetizing-looking yellow. It's from this premise that scientists figured out what might be going on.
Until 35 million years ago, the idea goes, large areas of the globe were covered with evergreen jungles or forests composed of tropical trees, say Simcha Lev-Yadun of the University of Haifa-Oranim in Israel and Jarmo Holopainen of the University of Kuopio in Finland. During this phase, a series of ice ages and dry spells transpired, and many tree species evolved to become deciduous, dropping their leaves for winter.
While the fall foliage in North America and East Asia takes on a fiery red hue, perplexingly, autumn leaves in Europe are mostly yellow in color. A team of researchers has a new idea as to why the autumnal colors differ between the continents, one that involved taking a step back 35 million years in time.
The green color of leaves during the spring and summer is a result of the presence of the pigment chlorophyll, which allows plants to capture sunlight and produce energy by the process of photosynthesis.
When the weather begins to turn cool in the fall, chlorophyll, which is sensitive to the cold, stops being produced. As the green fades, yellow and orange pigments called carotenoids (also responsible for the orange color of carrots) take over. These pigments were always present in the background of the leaves' color, but can finally shine through as the green diminishes.
While this process has long been known to scientists, the mechanism that results in red hues has proved trickier to understand, particularly because of the energy the tree must use to produce them at a time when the leaves are about to die anyway.
The red color comes from anthocyanins, which unlike carotenoids are produced only in the fall. These red pigments act as sunscreen for the trees by blocking out harmful radiation and preventing overexposure to light. They also act as an antifreeze, preventing leaf cells from freezing easily in the autumn chill.
Some scientists have even suggested that the red colors ward off pests that would munch on the leaves if they were a more appetizing-looking yellow. It's from this premise that scientists figured out what might be going on.
Until 35 million years ago, the idea goes, large areas of the globe were covered with evergreen jungles or forests composed of tropical trees, say Simcha Lev-Yadun of the University of Haifa-Oranim in Israel and Jarmo Holopainen of the University of Kuopio in Finland. During this phase, a series of ice ages and dry spells transpired, and many tree species evolved to become deciduous, dropping their leaves for winter.
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