Day 192: Lichens have been around for a long time. Obviously, they were preceded by algae, fungi and yeasts because all three are components of the structures we now call lichens, but they were already well established when herbivorous dinosaurs went looking for snacks. Many lichens reproduce both sexually and asexually, a factor which gives them a distinct leg up as to their survival capabilities. Sexual reproduction draws genetic material from two sources, mingling DNA to form new individuals. Asexual reproduction clones the parent material, i.e., the DNA of the new lichen is the same as that of the original. Ramalina farinacea rarely develops apothecia, the fruiting bodies which contain the spores necessary to sexual reproduction, but the margins of its lobes are often heavily populated with elliptical soralia containing hundreds of soredia, its vegetative clones. The soralia are quite obvious in the photo of a fresh specimen on the left. Can you spot them, still holding thousands of green and viable soredia, on the dried-up specimen on the right? Although the parent body is dead, it has the potential to live on in copies of itself. Barring a mass extinction of all life on the planet, I'm betting lichens will be around long after H. sap. has died off.
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