Sandfish Lizards

How to breathe under sand described in Journal of Experimental Biology (JEB) 16 November 2016, doi: 10.1242/jeb.151969.

The sandfish lizard (Scincus scincus) lives in the North African sandy desert and spends most of its life buried in sand. Scientists who have studied this creature have wondered why it doesn’t end up with its lungs clogged with sand, so a group of researchers from Austria and Germany studied how the creature breathed in an otherwise suffocating environment.

They carefully examined its respiratory tract, lungs and the digestive tract of dead and preserved lizards, and noted that there was sand in the gut but none in the lungs of any specimens examined. They also noted there was no structure that looked like an air filter. The only unusual feature was a region where the airway became narrow, then wider, and then narrow again. They also recorded the breathing pattern of live lizards.

To work out how the lizards kept sand out whilst taking in air, they constructed a model of the respiratory tract using a scanner and 3D printer. They then buried this in sand and blew gas through it using the lizards’ breathing pattern, and found that as the flow slowed when it passed through the wide region, any sand grains carried in the airstream dropped out and were trapped in a layer of mucus on the surface of the airway. When the lizard next exhales forcefully it blows any trapped particles out.

The research team concluded that the lizard was able to keep its lungs sand-free by an “aerodynamic filtering system” which combined the structure of the airways with “specific ventilation patterns”. They also described the system as an “adaptation to life in aeolian sand”. (Aeolian means wind-blown, as in sand dunes)


Editorial Comment: Did you note how much design and engineering went into making the model airway and getting it to work? Yet this team of scientists and engineers were only copying one part a lizard system that already worked. It would have taken far more creative design to invent such a system from scratch.

Evolutionary biologists regularly refer to features that enable animals to live in specific environments as “adaptations”, but to do so they ignore the serious issues of how would a surface dwelling lizard develop this system from a normal lizards’ breathing system, and how would it know it had the right structure in its airways before it started burying itself in sand? Getting lungs clogged with sand is not going to make a lizard develop this system. It will simply smother it, and the animal would be another dropout in the struggle for existence. Time to be honest evos: what you generally refer to as adaptations are really good design features.

Note the scientists concluded this is a dynamic system, meaning it combines both structure and function in order to work. The ventilation pattern is just as important as the shape of the airway and the presence of a mucus layer. This means the animal’s brain also has to be programmed to run the breathing muscles correctly, as well as direct the burrowing behaviour. This is a good example of a system that will only work when all the components are in place, and all such systems require plan and purpose in order to design all features then combine their total structure and function into an integrated system.

Give up evos, it is far more logical to believe this creature was designed to be a burrowing animal and was created with the correct working features from the beginning.

Evidence News vo. 17, No.1
1 February 2017
Creation Research Australia

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