The present day Giraffe has a long neck. It is due to
Lamarck’s theory explains that there is an internal force in all organisms which considers the new needs or desires of the organism, to produce new structures and change the habits of the organism and that, these changes are inherited by the next generation. Darwinism explains that there exist variations in organisms or species; and because of the struggle for existence in an ever - changing environment where nature (external force) selects the fittest species to survive; only those organisms with the right variations, survive and procreate. Hence, the giraffe that had a variation which gave it a longer neck, survived better than those that did not, and all giraffes today are descendants of that first giraffe that had a longer neck.