365Caws is now in its 14th year of publication, and was originally intended to end after 365 days. It has sometimes been difficult for me to find new material, particularly during the winter months, but now as I enter my own twilight years, I cannot guarantee that I will be able to provide daily posts. It is my hope that along the way I may have inspired someone to a greater curiosity about the natural world. If so, I can rest, content in the knowledge that my work here has been done.
Monday, October 7, 2019
Leocarpus Fragilis On Usnea Sp.
Day 359: If you were a slime mold, you would begin life as a single cell, having "hatched" (as it were) from a spore. Like any self-respecting cell, you would grow by fission. After reaching a certain state, you might encounter another compatible cell and, after a suitable cellular courtship, you'd join with it in a second biologic process called fusion. This fusion (similar to that of sperm and egg) would include the respective nuclei of both partners. The resultant diploid zygote would then feed and grow, its nuclei redividing and increasing, eventually resulting in a structure known as a plasmodium: a single multi-nucleate amoeboid cell. When various environmental factors align (food supply, temperature, light level, moisture, pH), the fruiting process is initiated (shown here in Leocarpus fragilis on an Usnea lichen). Inside the fruiting bodies, the protoplasm separates into units each containing a single nucleus. These undergo further division reduction until what remains of each unit is a haploid spore. When the sporangia (spore capsules) rupture, the spores are dispersed and the process begins again. That said, some slime molds have a secondary reproductive strategy to ensure the continuation of their species, and they will continue to populate the Earth long after we humans, so convinced of our own importance, are gone to dust.
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