Tag Archives: Science

Symbiosis: Lichen


Good morning Everyone!

Today we are going to take a walk into improbable reality:  the lichen.  While we tend to think of and treat lichen as one organism, it actually is composed of two (or more) organisms living together for each other’s benefit:  a fungus and an alga.  The fungus provides structure, support and water for the lichen, while the alga produces food through photosynthesis.  Because of this symbiosis, lichen are not considered to be plants.  (They aren’t animals either, nor minerals – so how do you answer the question “Is it animal, vegetable or mineral?” when it comes to lichen?)

Lichen, Wood

Lichen on Firewood by a House, Photo Credit: Nancy Eady

I became curious about lichen while we were living in our rental house.  The house owner had cut up a tree on the property, and placed the logs by the house.  Over time, rows and rows of fan-like shapes began to grow on the ends of the logs.  I took a picture of them, above.  As best I could determine, they were a kind of lichen.

Lichen Wood

Lichen in Wood, Photo Credit: Nancy Eady

Lichen are ancient survivors.  The oldest known fossil showing both symbiotic components of a lichen is 400 million years old, FN,  so it stands to reason that lichens are even older – it is highly unlikely that the first ever lichen was also the first lichen fossilized!  The variety and distribution of lichen is astounding.  There are over 20,000 known forms.  There are lichen that can colonize the most inhospitable of places, such as bare rock in the arctic, lichen that process and help break down inorganic matter such as wood, and lichen that seem to drift airily down in strands off of bushes and live off of the air.

Lichen, Letharia

Feathery Lichen. Photo Credit: Letharia vulpina JHollinger crop” by Jason Hollinger – Mushroom Observer. Licensed under CC BY-SA 3.0 via Wikimedia Commons

Lichen can live for astoundingly long periods of time; in fact, one lichen from the arctic circle is estimated to be 9000 years old!  I keep looking for a picture of this ancient lichen, but I haven’t located one yet.  I do know that the ancient arctic lichen is a member of what are commonly called “map lichen.”  As you can see, they get their name from the shapes they form on rocks, which resemble maps.  Their growth rate is incredibly slow, yet predictable, so they can be useful tools in dating other objects.  The use of lichen to date objects is called “lichenometry.”

Lichen, Rock, Map Lichen, Arctic

Map Lichen Photo Credit: Rhizocarpon geographicum on quartz” by User:Tigerente – Self-photographed. Licensed under CC BY-SA 3.0 via Wikimedia Commons

Lichen also provide scientists with helpful information about air pollution; most lichen are highly sensitive to air pollution, so if there is an area that normally would host lichen, yet has none, the air quality around the area is likely poor.

Aaliyah Gupta, Lichen, Acrylic on Duralar

Lichen, Acrylic on Duralar, By Aaliyah Gupta, Copied with Permission from the Artist

I have a friend in Seattle who is an artist, Aaliyah Gupta, and she worked on a series a few years ago exploring the symbiosis that creates lichen.  Her work is stunningly beautiful, delicate and unique, capturing the intricacies of a symbiotic dance that has persisted through the ages.

Aaliyah Gupta, Lichen

Lichen, by Aaliyah Gupta, Acrylic on Duralar, All Rights Reserved, Copied with Permission from the Artist

God’s handiwork is astounding.  Nature’s variety and inventiveness is unparalleled.  Taking the time to learn about other organisms on this planet always pays dividends – if only to make us realize how privileged we are to be part of the complex web of life traveling on Spaceship Earth!

Have a great day everyone!

Nancy

 

FN.  400 million years ago was the “Early Devonian Period.”  During the Early Devonian, plants and animals began to colonize land, while aquatic life was farther along and more diverse.  In other words, lichen pre-date dinosaurs, flowers, trees and grass!

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Bibliophilic Friday: Richard Fortey’s Life


Good morning Everyone!

Today on Bibliophilic Friday I am going to talk about one of my favorite non-fiction books on science, Life:  An Intimate History of the First Four Billion Years by Richard Fortey.  Nor am I alone in my admiration of this book; it recently was selected, along with another book by Richard Fortey, by the Folio Society in England.  The Folio Society publishes high-end editions of carefully selected books, and to have a book included as one of their offerings is an honor in and of itself.

Folio Society, Richard Fortey

The Folio Society Cover for Richard Fortey’s Life

I love to read about science, all aspects of it.  Richard Fortey is one of my favorite science writers because of the engaging way he illustrates his topics and the trick he has of making complicated concepts available to non-scientists.  In his book, Life, he covers the evolution of life from the first single-celled organisms through the present – and does so in a way that keeps you reading.

He has another quality as a science writer that I, as a Christian, find most endearing – he does not proselytize for atheism in his writing, something that spoiled some of the books of Stephen Gould and James Watson (the original discoverer of DNA) for me.  This does not mean that there is anything in his writing that promotes Christianity, either, but what it does do is leave me free to enjoy the science explained in the book without feeling defensive about my religious views.

(We’ll get into this more some other time – maybe – but I can study science and learn everything it has to teach me without giving up my religious beliefs, either.  Science is a study performed by man to understand the tangible world around us; Christianity and the Bible is a book given to us by God to understand the deeper, more important truths of where we came from , who we are and what our purpose in life is.)

As you read Life, you pick up on Fortey’s enthusiasm on his subject and learn about fascinating creatures – and not all of them are dinosaurs!  Even the algae mats that now exist in only a few places in the world but which once populated the earth in enough abundance to transform our atmosphere from primarily carbon dioxide to primarily oxygen can become interesting in Dr. Fortey’s hands.

trilobite

A Trilobite

Dr. Fortey’s academic specialty is the study of trilobites, animals that swarmed the oceans for over 270 million years but which became extinct about 250 million years ago.  Trilobites were arthropods, which means they are distantly related to insects, arachnids and crustaceans.  Their closest living relatives today appear to be the horseshoe crabs, which are often considered to be “living fossils”.  The horseshoe crabs are arthropods, too. Dr. Fortey admits in one of his books that he has a secret wish/hope that maybe just a few trilobites are still swimming around in the ocean, may in some deep-sea canyon, that have yet to be discovered.  I think that would be spectacular!

Horseshoe crabs

Horseshoe Crabs
From Wikimedia Commons; Photographer’s name not listed

Sorry – I digressed again. The point is that if you are looking for an informative, entertaining read that sets out a comprehensive history of life as currently understood by science, this is the book for you.

Have a great weekend!

Nancy