An amazing article about iron- both essential to life and toxic, sequestered in the core of the Earth, but needed at the surface

From crev.info

How Iron Fortifies the Earth and Life – CEH

2 minutes

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March 29, 2025 | David F. Coppedge

This article about the element iron
and its design was published in
Evolution News on 25 Jan 2022

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No Iron, No Life: Intelligent Design in Iron Availability

by David F. Coppedge
January 25, 2022

As an exercise, count the number of lucky breaks that had to occur for the evolutionary story to work.

Life relies on iron, but it is toxic, too. And it’s hard to get this scarce resource where it’s needed. Here is another case of fine-tuning that adds to the many Goldilocks “just right” conditions for life on our planet.

The Biophysics of Iron

Evolution News has reported on the gentle handling of iron by enzymes in cells, such as this discussion by Dr. Howard Glicksman, in which he describes the delicate interplay of iron and oxygen in hemoglobin that makes our blood red. He tells how specialized enzymes control acquisition, transport, and control of iron. Indeed, the building blocks of hemoglobin that incorporate iron, called heme molecules, are toxic within cells and also must be carefully handled, as this article relates.

Just how carefully can be seen in two animations of the CcsBA enzyme from research at Washington University at St. Louis. The enzyme molds itself around a heme (pictured green, with an orange iron atom at its center), preparing and assembling it for transport. It took the research team three decades to figure this out, and this is just the bacterial version!

As fascinating as these irreducibly complex systems are individually, they assume that iron will be available in the environment. How did that happen?

The Geophysics of Iron

Iron availability on the earth must be finely tuned. Iron in the Earth’s core, though abundant, will not be of any help to plant life on the surface or to ocean life. We observe that iron is abundant in crustal minerals, as seen in the colorful iron oxides that bestow reddish colors on many desert walls (and the planet Mars). Iron is also abundant in olivine, which can be delivered from the mantle by volcanoes. In a recent article, Evolution News described how “meteoric dust” from the solar system can gently rain iron onto the oceans for photosynthetic microbes like diatoms to use. But how did iron become finely tuned as to quantity and availability?

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