Final answer:
The two steps of epidermal development include the signaling by growth factors for some ectodermal cells to form epidermal cells, followed by the differentiation process where these cells express specific genes to develop into fully functional skin cells.
Step-by-step explanation:
Epidermal Development
The two steps of epidermal development during embryogenesis involve the differentiation of the ectoderm layer. Initially, growth factors signal some of the ectodermal cells to become epidermal cells, contributing to skin formation. Subsequently, the process of differentiation continues where cells in the ectoderm express specific genes, giving rise to the epidermis' characteristics and layers.
The epidermis itself further develops as new keratinocytes are formed at its base and move upwards, producing keratin and eventually forming a protective layer. This development is crucial as it ensures the formation of a waterproof barrier on the skin's surface, essential for protection against environmental elements.