Questions in Developmental Biology

Cellular Differentiation

• A fully developed organism has a diverse collection of cell types that work together to carry out the metabolic and physiological processes of life. All of these different cell types arise from a single cell, the fertilized egg. A process called cellular differentiation gives rise to muscle cells, skin cells, nerve cells, blood cells and the various other cell types found in the body. A developmental biologist is interested in studying how this occurs -- how one cell gives rise to so many different types of cells.

Growth and Organization

• The cells of our bodies do not randomly assort themselves to form limbs and organs. For example, the eyes are always found in the head and never in the gut, and fingers are always found on hands and never sprouting from the elbows. Developmental biologists are interested in studying the mechanisms that tell cells where to arrange themselves in the body and when to stop dividing or growing. Morphogenesis refers to the creation of ordered form.

Reproduction

• Reproduction refers to the ability of an organism to pass its genes on to a successive generation. Through reproduction, a species is maintained over time and avoids extinction. The sperm and the egg are very specialized cells meant specifically for reproduction. Developmental biologists are interested in studying how these special cells contribute to this process and initiate the radical changes that lead to the formation of a new organism.

Environmental Effects on Development

• Development is a dynamic process that can be affected by ambient environmental conditions. For example, the gender of developing crocodile embryos is determined by the temperature of the nest during the incubation of the eggs. Male crocodiles only develop when nest temperature is maintained between 89.6 to 91.4 degrees Fahrenheit, with temperatures outside of this range producing females. Additionally, it is well known that environmental toxins can have devastating effects on embryonic development, as has been observed in many aquatic species. Developmental biologists are interested in examining how differences in habitat during gestation contribute to an organism's final form and function.