Blue appears to be common in nature when observing the sky and ocean, but it is surprisingly rare compared to the prevalence of green hues found in plants and natural phenomena like the northern lights. Green is more commonly seen in vegetation, foliage, and reptiles, symbolizing the essence of the natural world.
The scarcity of blue is due to the complex principles of chemistry and physics governing color production and perception. These factors contribute to the limited occurrence of blue in the natural environment.
(Photo : Wikimedia Commons/Betty Wills)
The Mystery of Blue: Nature's Rare Optical Illusion
According to The University of Adelaide in Australia, blue can only be seen in less than 10% of plants and even fewer in animals. This rarity arises because plants and animals employ optical strategies to create the appearance of blue, as opposed to possessing a genuine blue pigment.
While plants utilize natural pigments, particularly red anthocyanins, whose color can be altered by varying acidity levels, animals rely on structural adaptations to manipulate light wavelengths and generate the illusion of blue coloration.
Unlike other color pigments, blue is not typically produced within an animal's body but is acquired through dietary sources. For example, flamingoes obtain their pink hue from consuming blue-green algae and brine shrimp rich in carotenoids.
However, the mechanisms behind the creation of blue coloration in birds and butterflies vary widely, encompassing microscopic bead designs and uniform crystal structures. This phenomenon is attributed to the physics of light scattering and interference, rather than chemical pigments.
Even in humans with blue eyes, the blue coloration arises from structural characteristics rather than pigment presence. Ultimately, the rarity of blue coloration in nature underscores the intricate interplay between biology, physics, and light reflection.
The Physics Behind the Rarity of Blue in Nature
To understand why blue is so rare in nature, we have to understand the physics behind it. Our ability to perceive color relies on the presence of light-sensitive cells called cones, of which the eye typically contains between 6 million and 7 million.
These cones are sensitive to different wavelengths of light, with three types being the most common: red, green, and blue. Signals from these cones are sent to the brain, where they are interpreted as various colors based on the types of light they detect.
When we observe colorful objects like sapphires or hydrangea blooms, they absorb certain wavelengths of light and reflect others, resulting in the perception of color. For instance, a blue flower such as a cornflower absorbs the red part of the light spectrum, causing it to appear blue to our eyes.
For a flower to appear blue, it must possess molecules capable of absorbing specific wavelengths of light, particularly those in the red part of the spectrum. However, producing such molecules is challenging for plants, which is why blue flowers are relatively rare, found in less than 10% of flowering plant species worldwide.
The evolution of blue flowers may be driven by their visibility to pollinators like bees, offering a potential advantage in ecosystems where competition for pollinators is fierce.
In general, blue is not only scarce in nature but also deeply ingrained in our language and expressions, appearing in numerous English idioms with varying meanings. This scarcity, combined with its associations with intangible elements like the sky and the sea, contributes to the versatile and often contradictory interpretations of the color blue.
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