Chapter 20 - Processes of Evolution - 20.2 - Mutation, Selection, Gene Flow, Genetic Drift, and Nonrandom Mating Result in Evolution - 20.2 Recap - Learning Outcomes - Page 434: 3

The evolution of the giraffe’s neck is an example of heterochrony. Like most mammals, giraffes have seven cervical vertebrae. These cervical vertebrae are much lengthier than those of other mammals as the result of the proliferation of cartilage-producing cells called chondrocytes. Apoptosis is used to regulate the development of chondrocytes and calcification of the bone matrix.

The evolution of the giraffe’s neck is an example of heterochrony. Like most mammals, giraffes have seven cervical vertebrae. These cervical vertebrae are much lengthier than those of other mammals as the result of the proliferation of cartilage-producing cells called chondrocytes. Apoptosis is used to regulate the development of chondrocytes and calcification of the bone matrix.