As you can see in this image of a beautiful Great Dane puppy, cropped ears maintain natural ear tissue at the front of the ear. (all-about-great-danes.com)
Rear ear tissue is actually what's removed and the length of the ear, from bell to tip, is up to you. (all-about-great-danes.com)
Researchers at Indiana University School of Medicine have successfully developed a method to grow inner ear tissue from human stem cells — a finding that could lead to new platforms to model disease and new therapies for the treatment of hearing and balance disorders. (sciencedaily.com)