This eclectic ZeFrank video was sent to me via reader Keith, who notes that ZeFrank is also on an “educational channel” containing videos that have been bowdlerized for educational use. But this one isn’t on it, and I think we’re all adults here. (“Jerry”, referred to several times, must be the producer.)
The first bit is about nematodes (“roundworms”), which inhabit a variety of environments and have a variety of lifestyles, including gross but fascinating parasites. The discussion of how parasitic nematodes infect insects, using electrostatic charge, is amazing, and the same method is used by ticks and mites. (There’s an ad between 4:22 and 5:38 but it’s for Planet Wild, which has a good mission.)
We then learn that electrostatic fields promote the pollination of flowers by bees. We also see again how bees use thoracic vibration to gather pollen, something that Athayde Tonhasca Júnior wrote about the other day. Finally, we get a lesson on the physics of how hatchling spiders disperse by spinning threads that they release into the atmosphere to drag them away from the hatch site: this is a way of finding a new and possibly better habitat.
As usual, the video is terrific and the science accurate.
Scary little bleeders out there doing their business, got a few tricks as well, nature sure is incredible.
Fascinating and beautiful.
Adult nematodes can be quite large. The common Ascaris roundworm that lives parasitically in the human small intestine is about as big as an earthworm. I think the image at 0:14 showing a tiny one is a first-stage “clump of cells” larva newly hatched from an egg (not necessarily ascaris.)
The second-stage larvae of hookworm having matured and molted in the soil where the host defecated have to penetrate the skin of the sole of the bare foot of a passerby — easier in children — in order to establish infestation as adults in the duodenum.
Now off to find out how the mouthparts of these filariform larvae penetrate thick skin and draw the rest of the worm in after it. I’m thinking of the swordfish being used as a bread knife in The Flintstones.
An EKG records the electric depolarization of the firing of cardiac muscles over time, using moist, gooey electrodes. It is done with the person supine and relaxed, as any skeletal muscle work would also be recorded and interfere with the recording of the heart.
Many years ago I was working in a neonatal ICU tending to a very sick, limp newborn girl. One of her 3 cardiac electrodes had fallen off, so her heart rate monitor was flatlined, but she was clearly alive. Without thinking it through, I put her electrode on my left wrist, to see if I could substitute her heart rate for mine. It failed, obviously. I then massaged her little feet with my right hand, and her cardiac monitor restored her heart rhythm. Her cardiac depolarization was strong enough to conduct from where I was grounding her with my right hand, through me, to the electrode on my left wrist. (Her heart rate was an expected 110-130bpm, mine was in the 60s)
After showing my attending pediatrician the next morning, he made a chain of 3 doctors holding hands, with one holding her foot and the the last connected to her electrode, and her heart rate was again on the monitor. She made a rapid recovery, which had nothing to do with our shenanigans.
Since then, I have felt that maybe kissing or holding hands is a way to share our electric fields with another person or critter. But, I do not want to think about it too much.