My life will never be the same. If you are squeamish, stop reading now.
A scanning electron micrograph of a female dust mite, size 0.25mm to 0.50mm. (Image by CSIRO via Wikimedia commons. CC-BY-SA 3.0)
Many people know about microscopic dust mites Dermatophagoides that live in our houses. Hordes of them live in the dust, in the mattresses, curtains and even in books. They quietly chew dandruff. I do not mind them, let them chew, there is no dust mite allergy in our family. I am happy to participate in the circle of life via discarded matter.
Demodex under the microscope. (Image by Blauerauerhahn~commonswiki via Wikimedia Commons. GNU 1.2)
But I was told about “the other” mites, Demodex, which live on the skin of almost everybody. Demodex especially love to hang the tail in the hair follicles and sebaceous glands while chewing on fat and bacteria. If the host’s immune or hormonal system is weak, they can become a problem. Demodex are everywhere but they are not contagious.
As a microbiologist, I welcome bacteria and yeast on the skin but in my opinion, mites are too much. The mites should look like the dust one – insect-like, with a body and legs. Demodex with its long tail and various protuberances near the head reminds me of something completely different, see below
… five-fingered hand is an accident, not inevitability. Many ancient amphibia had 6-7-8 fingers, but their descendants did not survive until our time. Imagine how beautiful a piano concerto for 8-fingered musicians would be.
2 hands + 2 feet body plan is not an inevitability either, just a result of a fish with two front and two tail fins crawling on the land. The ancient fish had different fins arrangement, including extra pairs of fins. I think two pairs of hand would have increased the brain size as well – probably we would have colonised the Solar system by now.