From a web page on logical fallacies:
Bad Analogy:
Claiming that two situations are highly similar, when they aren't. For example, "The solar system reminds me of an atom, with planets orbiting the sun like electrons orbiting the nucleus. We know that electrons can jump from orbit to orbit; so we must look to ancient records for sightings of planets jumping from orbit to orbit also."
Or, "Minds, like rivers, can be broad. The broader the river, the shallower it is. Therefore, the broader the mind, the shallower it is."
Comparing man-made machines with animals is definitely a bad analogy.
It simply has yet to be demonstrated to me WHY the comparison of machines to living beings is necessarily a BAD analogy. Webster's definition of analogy follows ...
... similarity or agreement between one thing and another; resemblance; comparison.
Now, of course, there are differences between machines and living beings. If there were no differences, any analogy would be meaningless. The point is, despite the differences, THERE ARE similarities in the form and function of machines and living things. Some of the similarities are ...
... the complex interaction of components and systems which provide for their respective functionality.
... the gradual wear and eventual breakdown of these same components and systems which eventually leads to the failure of function.
... the conversion of energy (provided by some type of fuel) to function.
... the existence of a control center (whether mechanical, electronic, chemical, etc.) which regulates and constrains function.
Of course, ultimately, the validity of any analogy is in the eye of the beholder. Some folks just won't get it.