I am following a course on “physics of organs”, and found something interesting:
(…) when a key component of the respiratory system fails in a higher organism, external respiration [breathing] becomes more like that of an organism lower on the evolutionary tree.
- a failure of a mammal’s air pump makes this individual behave more like a unicellular aquatic organism without cilia [water pump organs].
- A reduction in the surface area of the alveoli [minuscule air sacs] in a mammal creates the same problems faced by an amphibian with simple sack-like lungs.
- A major shunt in the circulatory system [mixing of high and low oxygenized blood] makes a mammal behave more like a fish.
- In severe anemia [lack/dysfunction of red blood cells for oxygen transport], a mammal faces the same problems as a lower life form with a less efficient respiratory pigment [oxygen transportation].
From Medical Physiology by Boron & Boulpaep
Now, while dysfunctional breathing can easily lead to regression “down” the evolutionary tree, the opposite is not the case: we don’t see movement “up” the evolutionary tree due to dysfunction. For me, this is an interesting illustration of the explanatory power of biological evolution.
I am curious about two things:
How do young-earth creationists deal with such observations? Do they picture God as “incrementally” designing all species in His mind before creating them?
What are other clear examples of such “stepwise functionality” across organisms that recaps the evolutionary tree? Maybe the biologists in the room can help out here.