BIO 448
MOLECULAR BIOLOGY OF
DIFFERENTIATION
Segmentation
• Distributes gene-regulating Substances.
• Morula
• Blastula
• Gastrula
The details of cleavage are different
between species.
Gastrulation Creates Three Tissue Layers
• Endoderm
• Ectoderm
• Mesoderm
Cellular Environment Affects the
Development Fate of Cells
Adult Structures Develop During Organogenesis Ectoderm, endoderm and mesoderm gradually
rearrange themselves to organs that are characteristic of animal species.
This process, called organogenesis, is normally performed by induction.
Sexual Maturation is Controlled by
Genes and the Environment
Aging is Programmed Genetically.
How Do People Develop?
• Human development is controlled by the same mechanisms that control the
development of other animals.
• Placenta secretes hormones and replaces materials between mother and embryo.
• Placenta only provides partial protection.