Lichen History Revised

Posted on November 20, 2019

As in any well done science work, new information that can be verified may change our understanding of the world. We can only learn ‘the next step’, we can never completely know the depth and complexity of the world from any one perspective. And so now lichenologists have found something new going on in lichens that revised our understanding of when lichens first appeared on earth as well as what makes a lichen; at least certain lichens. I suspect they will always fool us; they are too complex to box into a category and leave them there.

The study originally looked for reasons some fungi and algae ‘hug’ each other and don’t let go. But along the way, the evidence seemed to show that fungi figured out how to do this in many places and times, not just from one ancestor. The earliest fungi to do this, that humans have evidence of so far, do not show up before ferns and a few other plants. So it may be that lichen did not colonize land before plants.

There may still be more surprises in the fossil records, and we may need to revise this story again in the future. It’s like a big puzzle; each piece is useful but only part of the picture. Even though we don’t have the whole puzzle figured out, we do see part of the story. Making adjustments, like sorting pieces-sky pieces we know go near the top of the puzzle, water pieces near the bottom- helps understand the patterns of life on earth even as we continue to search for the details.

For a life as simple looking as lichen are (to us), they do have amazing abilities to be flexible and adaptable; traits we might find useful. So the scientists continue to look for why and how the lichen do what they do, and I’ll let you know when I find out too!

(The title image is Chicken-of-the-Woods, growing behind my horse barn, on an old log.)