In humans , the growth of a baby inside a mother takes about 9 months. In mice, rats and birds this growth only takes about 3 weeks. During this time a single cell will grow into many different cell types with different shapes and jobs to do in the body. A similar process will occur in all different embryos. In humans, many important changes occur in the first weeks of development and much of the remainding 9 months is growth.
Lets follow the growth and changes in the embryo over time.
It is also difficult to make Notes suitable to cover the entire K -12 age group. For younger students I suggest showing the movies of embryo growth and other movies from the Links below. Also the Other Embryos pages also has many pictures of different embryos. 16 to 20 Week 21 to 25 Week 26 to 29 Week 30 to 34 Week 35 to 38 Birth Note that these descriptions have been made simple for the younger K12 student. There are also links to the same material for University students on most pages.