I agree with many other people that "family" is the taxonomic level that best approximates "kind".
That's a huge problem for flood believers. Let's look at a simple case, the Equidae: there are 37 recognized genera, all but one are extinct. The genus Equus includes 22 recognized species of which 7 are extant.
The Felidae include 43 genera, of which 15 are extant. In those 15 genera there are 41 species.
The canidae includes around 290 species. These overlap extinct species in extant genera. There are 13 extant genera with 36 extant species.
So, are all of the extinct species pre-flood? Where did they all come from? Were they all created kinds? Or did they hyper-evolve from created kinds in the few years between the creation and the flood? Which were the "kinds" that Noah took aboard the ark and how did the extant species evolve at such hyper-evolutionary rates from a single pair in only a few years? I'm an evolutionary biologist and the thought of evolution at such rates makes my head spin.