Back yard nature: the short lives of dandelions

We had a couple of early dandelions awhile back, but they're all out in full force now.  Here is what puzzles me: of those that blossomed early this week, some are already white fluff and seeds.  How can dandelions be so short-lived?

Back Yard Nature: Two firsts today

In our back yard:

First dandelion.

First violets.

Spring is definitely here.

Photo from Wikipedia.