Copyright protects an artistic, literary or musical work. It is, literally, a right to stop someone copying a piece of work. There is no need for the thing to have artistic merit ("artistic work" is a term that covers art and photography, and is descriptive rather than qualitative).
The right arises automatically and is given to the creator of the work (known as the "sweat of the brow" test) but there are some exceptions where the work is created in the course of work, where the copyright automatically passes to the employer, and it is common for employment contracts to include the automatic assignation of copyright - so don't anyone get excited that they own their spreadsheets.
As an aside, moral rights give the creator of a work the right to be identified as its creator even when they don't own the copyrignt (see, for example, yer 2000ad credit card).
What's more interesting is that to breach copyright, you have to actually lift the thing that is protected and copy - that is, duplicate - it. Varying a piece enough can generate a new copyright in and of itself. The question is "what is enough?" - this was endlessly debated when sampling became popular and is a minefield, especially when you get into questions about crediting art, photos and snippets of music.
However, with text it is simpler.
YOU CANNOT COPYRIGHT AN IDEA.
Rather, what you can copyright is the expression of an idea. Eg you can copyright the recipe for Coca-Cola, but all you are doing is preventing the words on the page being dupliated. If someone else knows it then they can go and make it without breaching copyright.
The same thing goes for story ideas, folks. That's why Hollywood is free to cannibalise itself. Even if two films or books or comics or games or whatever share similar characters (in terms of traits), plot and twist - if they are different in terms of image and words on the page then it becomes difficult to show breach of copyright.
So, if you are not lifting words wholesale, then it becomes difficult to show that one piece of work is breaching the copyright of another simply by using a similar expression - although it becomes easier when unique or made up words are involved. Hence, I doubt "Jurassic F**k" would be a breach of copyright in and of itself because - as a title - it is simply two common words run together.
If the porno was shot to be similar to another film (Jurassic Park) then it might be easier to show breach of copyright, and it would be easier still if it used footage. But then you run into nebulous "fair use" and "parody" arguments. The law here differs a bit between US and UK (most IP law is derived from global convention and roughly similar throughout the West).
Trademarks, however, are a differnet kettle of fish. A trademark (normally a logo or "get up" and possibly including a combination of words, like "Jurassic Park") is a registered "device" - the coke logo, the 2000ad logo, store names like Tesco and so on are other examples. It costs to register and maintain a trademark, and you sometimes need to have been using them a while before the protection becomes available. Once registered, it is reasonably straight-forward to show that anyone using a similar sounding name (if you have something unique, like "Judge Dredd" or "Jurassic Park") is infringing your trademark. This is a detailed process, but basically it is a claim that someone is benefitting by making an assocaition with your trademark that is not what you want and not to your benefit.
Hence, if "Jurassic Park" was a trademark it might be easier to establish trademark infringement by "Jurassic F**k" than copyright infringement.
Believe it or not, I've tried to avoid detail here - so take independent legal advice about your situation and don't rely on internet posts for advice!
Aside: fact fans: the difference between (R) and TM is that (R) is registered, while TM indicates someone intends to register once they have used the get up enough. Again, a gross simplification, but there you go.
