How are “the origin of human” and “the origins of human” used differently?

Statistically, I have searched on Linggle, on which "the origin of human" appeared 5900 times, and "the origins of human" 5500 times. It seems both are used.

What I can come up is the topic about, "multiregional hypothesis" and "recent single-origin hypothesis", and those who support the former use "origins" those who support the latter, but what if the speaker/writer is not sure which to believe in and or just has no idea about the topic?

I feel there might be other aspects that take place and decide the number, but since my L1 has no distinction between grammatical numbers, I have only vague language sense about the numbers, especially concerning abstract conceptions like "origin".

And is there a "default" number, if you are not sure if there’s/are one or many? I remember that you use "I hear birds singing" rather than "I hear bird singing" if you are not sure about the number but just hear the sound. How about abstract words like "origin"?

Edit:

Thanks for pointing out the form of "human". I again searched by "humans". It turns out 1500 "the origin of humans" and 1000 "the origins of humans".

There are found some example of "the origin of the human race", "the origin of the human races" and "the origin of hominids", but there is found no result by their plural form.