The Best in Show winner at the National Dog Show presented by Purina will be selected from among seven finalists, those dogs that were chosen the champion in their respective groups, which are Sporting, Hound, Working, Terrier, Toy, Non-Sporting, and Herding. As part of NBCSports.com’s special coverage of this competition, below is a look at these groups.

SPORTING GROUP
The invention of the gun led to the development of the sporting or gun dogs to aid in hunting of upland game birds or waterfowl, performing at the direction of the hunter.

While a number of these breeds perform more than one task, it is generally the duty of pointers and setters to point and mark game; for spaniels to flush game; and for retrievers to recover dead and wounded game.

There are 27 breeds and varieties in the Sporting Group.

HOUND GROUP
Originally classified as sporting dogs because of their function as hunters, breeds in the Hound Group are of a great variety of size, shape and coat.

Most of these breeds were developed to hunt somewhat independently for their owners, who usually followed on foot or on horseback as the hounds chased down the prey.

This group informally consists of scent hounds -- those dogs that hunt by tracking a scent, and sighthounds, who spot their game and run it down.

There are 25 breeds and varieties in the Hound Group.

NON-SPORTING GROUP
The AKC originally registered dogs as either Sporting or Non-Sporting.

Eventually, hounds and terriers were split from the Sporting Group, and the Toys and Working dogs were split off from Non-Sporting, with the Herding Group eventually splitting from Working.

Today, the Non-Sporting Group is literally everything that is left over, resulting in a great variety of sizes, shapes, hair, function and history.

There are 18 breeds and varieties in the Non-Sporting Group.

TOY GROUP
Toy dogs have been around for centuries, and are bred for one purpose, to be companions for their owners.

Many have been bred down from and still resemble their larger cousins.

Their small size and portability make them ideal for city dwellers and those with limited space.

There are 22 breeds and varieties in the Toy Group.

HERDING GROUP
Herding is a natural instinct in dogs that is seen in the wild.

Humans have turned that instinct to their use on farms and ranches with herding dogs, who have the sole purpose of moving livestock from one place to another.

Among this group are the collie and shepherd dogs.

There are 19 breeds and varieties in the Herding Group.

WORKING GROUP
While the uses and appearances of the dogs in the Working Group vary, most are powerfully built and intelligent, performing various tasks for their owners.

These dogs are working farm and draft animals.

They guard homes and livestock, serve heroically as police and military dogs, security dogs, guide and service dogs, and hunting dogs.

There are 21 breeds and varieties in the Working Group.

TERRIER GROUP
All but two of the terriers evolved in the British Isles.

The geography of the specific area (water, rocky terrain) helped to determine the exact duties of each breed, but usually it involved hunting vermin and varmints ranging from rats to badgers to otters and more.

These are dogs of great determination, courage, and self-confidence, with a great willingness to go to ground in search of quarry.

There are 27 breeds and varieties in the Terrier Group.