Theory In Crisis: Ii
If function is king, then there aren’t any Types,
but the living show us that’s simply not true.
The class tree is ordered according to forms
and not by the functions a critter can do.
So here’s a conundrum you might find odd:
a superclass known by the name Tetrapod.
Vertebrates these, the four-legged animals:
reptiles, amphibians, and also mammals.
Dinosaurs found here and therefore the birds;
The scope of this superclass: rather absurd.
A feature that all of these share in common:
Four pentadactyl limbs, from the top to the bottom.
Think humerus, radius/ulna, phalanges,
or femur, tibia/fibula, toesies.
All of these critters, extinct and alive
share a limb bone pattern of one, two, and five.
I know that you’re thinking I’m proving the point:
With all that evolving, we must Darwin anoint!
The fittest survive, “Change or Die!” what they say
So why does that one-two-five get in the way?
Are you telling me that to swim, run, or fly
that the one-two-five pattern is the best of all tries?
In bats, five fingers prominent, birds show just two,
But during development, all five are in view.
If you look at a horse or a pig, it’s a ruse!
But in the embryo, those bones will fuse.
No matter the adapting it takes to survive,
They always start out with the one, two, and five.
Three hundred sixty-five million years past:
that’s when the pentadactyl pattern was cast.
What in the world caused this weird isolation?
Such fixation defies Darwin’s explanation.
The limb is just one of the numerous features
that uniquely identify classes of creatures.
An a-functional body plan resisting change…
Even Gould veered from Darwin, finding this rather strange.
Copyright ©
Jeff Kyser
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