One finger, one thumb, one arm, one leg, one nod of the head, sit down, stand up, keep moving We'll all be merry and bright
I want a creature that literally has one of everything.
All of the above plus:
One eye, One nostril, One nipple, One foot, and so on.
The creature moves by hopping (of course) and it manipulates things with a combination of its tail and its one hand (which has one finger and one thumb).
I only want to consider macro features. It would be ridiculous to have only one brain-cell, although some people might think that applies to me.
If we assume that this is some future type of Earth-creature that has evolved over thousands or millions of years from a kangaroo, are there any insurmountable biological reasons to prevent it only having one of every major organ. It seems to me that it could have one liver, one lung, one kidney etc. and survive perfectly well.
Anatomically and medically is there any reason that such a creature's macro-scale internal and external structure could not be viable?
Assume the creature is pretty much bilaterally symmetrical on the outside and probably on the inside as well.
I'm interested at the organ level rather than the cellular level.
As I mentioned the creature is descended from a kangaroo. From the side it would look exactly like a kangaroo. From the front it would look like a one-eyed, one-eared, one-legged kangaroo. I'll see if I can produce a picture although this may not be easy.
How the creature evolved
First of all the legs fused centrally. This is because a present-day kangaroo always uses its legs in unison when travelling, two separate legs became unnecessary. The arms merged and the nostrils merged. I haven't yet come to grips with the fusing of two eyes into one. It may be better to preserve two so as to allow binocular vision. The genitals of both sexes migrated to the front and the anus to the back. Mating is done face to face. The reason for this is to allow the newly born joey to crawl into the mother's pouch. The joey as you know is quite primitive at birth and it retains some of the old kangaroo features to allow it to climb. As it develops further the new physiology develops in a reiteration of what happened during evolution.