This is a colourful planet. It’s a space filled with countless colour spectrums and hues, visually spectacular. Without colour, life would be monochromatic dullness.
This is a colourful planet. It’s a space filled with countless colour spectrums and hues, visually spectacular. Without colour, life would be monochromatic dullness.
Colour is important in life. “But is it important to life?” That was the question posed by Prof Martin Stillman, the keynote speaker at this year’s Barker lecture, held last Tuesday at Rhodes University‘s Chemistry Minor.
To anyone with the slightest knowledge of biology, the answer would appear obvious. Chlorophyll is the 'dye' or pigment responsible for the green in plants, and porphyrin in haemoglobin (or heme b in scientist lingo) gives us the red in blood.
Both are inherent to our view of the world. But Stillman, who is the head of bio-inorganic research at Western Ontario University, illustrated that there’s more to this than substance colour-coding.
Light is as important, if not more so, than pigment. If living organisms, such as plants, were exposed to light at heightened frequencies over a prolonged period of time, chances are their development would change accordingly.
And living beings' response and adaptation to light, in many ways defines how they survive and evolve. Ultimately, colour and light are dynamic phenomena that change according to circumstances.
Twenty thousand years ago, for example, our planet was in a dilemma. The high dust content in air cut out UV light.
Given this fact, plants could well have been red or purple – but they weren’t. Nature devised creative way to ensure plants remained green.
The question that this poses is what and how big a role the colour of molecules plays in creating life on this planet. And if there is such a role, could a particular level of light absorption serve as an evolutionary trigger in plants?
Stillman believes the answer lies in investigating the response of aromatic organic compounds like benzene to various light sources.
“We know plants absorb light for electrons, which translates to energy," he said. “I was looking at all these molecular rings and I finally realised that the most fascinating one of them all was right in front of me.”
So what was it? “Grass.”
Because grass contains light and pigment, all the necessary ingredients for Stillman’s hypothesis.
More than anything, Stillman believes that colour and light are probably driving the evolution of flora today. “Somewhere there must be a plant thinking to absorb waves beyond UV light.
"Somewhere out there a plant is thinking about absorbing enough light, developing muscles and starting walking,” he said.
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