grizzly bear photo
With no punctuation in the query, the software interprets grizzly bear as a phrase and photo as a separate word. Pages with the phrase grizzly bear (those words together in that order) and photo will appear at the top of the match list. Then will appear pages with all three of these words in any order.
"grizzly bear" +photo
The plus (+) sign means only include pages that contain the word photo. Quotation marks delineate a phrase. Pages with both photo and the phrase "grizzly bear" would appear at the top of the list; then would come pages with photo but not "grizzly bear". Pages with "grizzly bear" but not photo would not appear.
"grizzly bear" photo
This query matches all pages that have either the phrase grizzly bear or the word photo. Pages with both go to the top of the list, so in most cases the top results will not differ from the above examples.
grizzly bear -photo
or
"grizzly bear" -photo
Both these queries yield pages on which the phrase grizzly bear appears and that do not contain the word photo.
