Question

You are conducting an experiment by trying to reproduce the work performed in 1891 by

Hans Driesch, a German embryologist. You are working with a fertilized sea urchin egg and
allow it to complete the first cell division after fertilization. You then carefully separate the two
cells of the embryo and allow their development to continue. Based on Driesch's experiment,
which result below would you expect to happen?
a) Both of the cells will die.
b) Both cells develop into complete and normal embryos that are somewhat smaller.
c) One cell develops into a normal, though smaller, embryo; the other dies.
d) One cell develops into half an embryo; the other develops into the other half of the embryo.
e) One cell develops into a defective embryo and the other dies.

Answer 1

The expected result from separating the two cells of a sea urchin embryo after the first cell division, according to Hans Driesch's experiment, is that both cells will develop into complete and normal embryos, although they will be smaller in size.

Step-by-step explanation:

The expected result of Hans Driesch's experiment when separating the two cells of a sea urchin embryo after the first cell division is b) Both cells develop into complete and normal embryos that are somewhat smaller. This outcome is due to the totipotent nature of early embryonic cells, meaning each cell has the potential to develop into a full organism. Driesch's work was pivotal in demonstrating cellular differentiation and the developmental potential of individual cells within an embryo.

In the early stages of embryonic development, such as the sea urchin's development from a zygote, cleavage leads to the formation of blastomeres, which are capable of developing independently into complete embryos. This is possible because these early cells have not yet undergone specialization and possess the entire genetic information required for the formation of an organism. This phenomenon is especially evident in organisms like sea urchins and is a key concept in developmental biology.