Doesn't sound to me like something unique to evolution theory.
Nonetheless, that is what people typically mean when they refer to 'evolution'. However, the latter part of your post shoes that I should have qualified my statement better.
You do realize this is also a fact in the biblical sense, right? - In the beginning God created the heavens and the earth. - Gen 1:1.
Perhaps, but I don't see its relevance when talking about scientific nomenclature.
Are you referring to our universal COMMON ANCESTOR, GOD, who produced different species having similar body parts, like fingers and toes?
No. I'm referring to the organism from which we are all biologically descended, not supernaturally created. According to the theory of common descent, which may be entirely wrong in the details or the particulars, we share an ancestor with all life on Earth in the same way two cousins share a grandparent.
Humans and apes are both biologically equipped by their COMMON ANCESTOR, GOD, this explains their many similarities, they are using much of the same biological equipment provided to them by our universal COMMON ANCESTOR, GOD.
Perhaps, but evolution argues differently. According to the theory of common descent, the reason both humans and chimps have five digits is because they both are descended from a single species which had five digits - likely an extinct species of primate about 5-7 million years ago.
I sometimes think that a scientific theory is a scientist' attempt at offering a natural explanation for every observation.
Depends on which scientists you talk to. Depending on how you define 'supernatural', there are two common approaches:
First, you can do what I do - reject the distinction between 'natural' and 'supernatural' as meaningless. There are simply phenomena. If 'Goddidit' is the truth, then that is the truth. I would go so far as to say it's a naturalistic explanation, since anything that can potentially influence us is a part of nature. If gods, ghosts, and goblins exist, then they are natural and physical.
Second, you can reject supernatural explanations as being fundamentally implausible - there is nothing we know of that requires a supernatural explanation. Scientists prefer natural explanations because
all known explanations are natural. Thunder? Babies? Card tricks? All explainable by wholly natural phenomena. In this view, supernatural explanations are valid, but just hopelessly implausible. God
could be up there in the clouds throwing thunderbolts at church steeples, but the evidence points to a wholly natural (i.e., static electricity) rather than supernatural (i.e., God) explanation.
So, scientists are preferentially naturalistic because that's just what works. Show us the supernatural, and we'll accommodate it. Ghosts may indeed exist, and there's nothing inherent about science that forbids it from investigating them. Depending on how you look at it, this either means the supernatural is not exempt from scientific scrutiny, or that ghosts aren't actually supernatural.