Service Provider IoC, bindings diferrence

I have in my service Provider the following code in register function

use App\Modules\Core\Includes\Services\Human;

public function register() 
{

$this->app->bind('human', 'App\Modules\Core\Includes\Services\Human');

$this->app->bind('human', function() {
    return new Human();
});

}

What is the difference between this two binding ?