From what I got to study the biology of animals you must:
1. Only pictures are not sufficient to know about the internal structures of animals. The anatomy describes about the internal morphology of the organisms.
2. So, for better understanding of the internal structures of animals, the student biology dissect the animals in the laboratory.
3. Dissection is an important practical for biology students.
Now this is what I got but it's somehow similar to this subject but, I hope this helped a bit.
