This explanation is true and describes how the form reflects the meaning, but doesn't deal with use. Have a look at the Communicative Grammar again (in my very old edition it's section 74, but if you have a newer edition and it doesn't correspond, just look up
the -generic reference in the index) and you'll find :
The definite article also has a generic use referring to what is general or typical for a whole class of objects. This is found with count nouns :
The tiger is a beautiful animal.
Here "the" indicates the class of tigers, not one individual member of the class.
(My underlining)
and later they say :
.. when we are dealing with a whiole class of objects the differences between definite and indefinite, singular and plural, tend to lose their significance. There is, however, a slight difference in the fact that "the tiger" (generic) refers to the species as a whole, whereas "a tiger" (generic" refers to any member of the species. We can say :
The tiger is in danger of becoming extinct.
but not : *A tiger is in danger of becoming extinct.
Your essay title, as I said in the first reply, did not mean
Advantages and disadvantages of owning the class/species "dog" but the
Advantages and disadvantages of owning any one dog - ie an individual member of the species. Therefore here, the definite article can't be used.
The use of the definite article is actually relatively rare - a) because we make generic statements about classes relatively rarely and b) because the plural can be used to refer to classes of objects as well - and I think we tend to use that form more. It expresses the notion of "all tigers" (or whatever).This is probably why all the examples of the definite article used generically tend to involve tigers. No-one can think of any other examples
So in summary :
- The definitete article + singular or zero article plus plural you specify for countable nouns can all be used to express generic reference to a class of objects. Intuitively, I'd imagine that the plural is probably the most common, but I don't have any evidence to back that up.
- When referring to any individual member of the class, the indefinite article + singular will be used.
If in doubt try "expanding" the statement :
- You can use The+singular if you can say
The species - eg
The species dog is carniverous but not *
Advantages and disadvantages of owning the species "dog", because you can't own a complete species. You just own individual members of that species.
- You can use the plural if you can precede it with
All :
All dogs are carniverous but again not *
Advantages and disadvantages of owning all dogs, because you don't own all dogs - you just own one or two or some other number of them.
- You can use a/an+singular if you are speaking about any one individual member of the species any
single member of the species :
The advantages and disadvantages of owning any dog. - ie it doesn't make any difference whether your dog is a Chihuahua or a Great Dane - the statements you make will be true for that particular dog.