Animals without a nervous system + Here's how flying snakes stay aloft

Human-guided evolution closer than you think

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Can some animals really exist without a nervous system?

EXCERPTS: The nervous system is what allows us to sense our surroundings and act in the outside world. All our thoughts, senses, actions and movements are based on it. The same goes for all other animals we are in contact with: dogs, horses, starfish, ants, earthworms and even animals as simple as corals and jellyfish. It is hard to imagine how an animal would be able to cope without a nervous system.

Trichoplax belongs to the placozoan branch of the animal kingdom, and it is one of the most primitive animals there is. It consists of multiple cells, and it is therefore - despite being similar in appearance - not related to amoeba. The structure of Trichoplax can best be described as a one millimetre thick sandwich that consists of two layers of surface cells with a single layer of inner cells. In total, there are six cell types: upper epithelial cells, lower epithelial cells, fibre cells, lipophilic cells, gland cells and crystal cells.

Despite the simple structure, Trichoplax has been a great success evolutionarily speaking [...] Trichoplax possess one of the smallest genomes ever studied. Most surprisingly, however, it also turned out that Trichoplax possess virtually all the machinery needed to have a functioning nervous system. But there is one problem: on closer inspection of Trichoplax under a microscope, there is no evidence that there are nerve cells.

But despite the lack of a nervous system Trichoplax is able to perform relatively quite complex behaviours. Trichoplax, for example, can move, sense the presence of food, stop and devour algae, and sense gravity. This may sound very simple, but considering what Trichoplax has to work with, it does it pretty well. Keep in mind how essential the nervous system is to all other animals; without it we would have no senses, thoughts or actions. But how can the individual cells in Trichoplax agree on what to do? (MORE - details)

Here’s how flying snakes stay aloft

INTRO: The movie "Snakes on a Plane" had it wrong. That’s not how snakes fly. Certain species of tree snakes can glide through the air, undulating their bodies as they soar from tree to tree. That wriggling isn’t an attempt to replicate how the reptiles slither across land or swim through water. The contortions are essential for stable gliding, mechanical engineer Isaac Yeaton and colleagues report June 29 in Nature Physics.

“They have evolved this ability to glide, and it’s pretty spectacular,” says Yeaton, of Johns Hopkins University Applied Physics Laboratory in Laurel, Md. Paradise tree snakes (Chrysopelea paradisi) fling themselves from branches, leaping distances of 10 meters or more. To record the snakes’ twists and turns, Yeaton, then at Virginia Tech in Blacksburg, and colleagues affixed reflective tape on the snakes’ backs and used high-speed cameras to capture the motion... (MORE)

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