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A Homily On The Green We're Seeing Again

One thing we celebrate at this time of year is that winter’s grays and browns are being gloriously replaced by the signature of new growth: the color green.  

From fully leafed-out forests to roadside poison ivy, nature’s process of photosynthesis is back at work after a long winter of near-death inactivity.

When I taught middle school science I had T-shirts printed for my kids with the words “Photosynthesis – Not just chemistry, this is poetry.” I always waxed rhapsodic when we came to the subject of photosynthesis. The complexity of what happens is almost mystical.

The magic takes place inside every cell of every living plant, where there are tiny green chloroplasts. To perform their miracle, chloroplasts require sunlight during the day and air temperature warm enough for water to exist as a liquid.

Photosynthesis is about drawing simple stuff in — water and carbon dioxide — and turning it into something more complicated: glucose, the simplest food and pure oxygen, which it launches into the atmosphere. Now we have food for animals to eat and oxygen for them to breathe.

The balanced chemical formula for this process is beautiful in its symmetry and simplicity. Six molecules of water and six of carbon dioxide produce one of food and six of oxygen.

This miraculous process has been going on, enriching our atmosphere and feeding animal life for billions of years. 

I preached this homily to my sixth-graders while we studied the evolution of Earth.

Before there was a life-sustaining atmosphere here, there was an abundance of primitive plant-like bacteria, stromatolites, that lived in the warm shallow seas. The limestone mounds they created are Earth’s oldest fossils. Here's where it all started. For billions of years, stromatolites slowly and constantly bubbled life-giving oxygen into Earth’s atmosphere. And they're still doing it off the coast of western Australia.

I'm not alone in thinking stromatolites deserve a tip of the hat.

At the end of their unit on Earth's geologic history, sixth-graders hung their illustrated geologic timeline in the school's hallway. Some suggested we make some kind of shrine to honor the humble stromatalite. They understood. Photosynthesis — not just chemistry. This is poetry.

Toby Goodrich taught science for many years at the Renbrook School in West Hartford, Connecticut.

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