trying to recall the name/author of a story I read years ago

(A kindly soul on the ABC science forum referred me here - hope someone can help - it is starting to drive me bonkers!)
I am trying to identify a science fiction story I recall from my teenage sci-fi phase 30-odd years ago.

It was about someone/ something who was collecting (or making?) specimens of every creature, and by the end of the story you realise he/she/it is creating life on earth. I only really remember the fact that at the end you realise it is about the creation of life on earth (not in a religious way), the rest is sadly vague, which is why I'd like to find it and read it again!

Does this vague plot ring a bell with anyone?

I have tried internet searches to no avail. I thought it might have been an Asimov but I can;t find anything similar in lists of his stories. I also searched for Bradbury, and Arthur C Clarke, but it could be any author that was around before the 70s really.
At the time I mostly read collections of short stories, which is why I think it was a short story rather than a novel - but I could be wrong. (Maybe I imagined the whole thing?)
I'm sorry to say that if it was a short story, it may be impossible to locate. It's an issue of it being a needle in a haystack.

There have been a number of short stories written with this general theme, though; you might be able to find a similar one?

Could it have been a TV show?