What is an unfertilized ostrich egg? Is it a cell, tissue, organ or organism?

Answer

Dear Jasmine,

since you participated in the bio-olympiad you probably know the difference between a cell, tissue, organ or organism, so I won’t go into detail here.

An unfertilized ostrich egg may seem a bit confusing since it is composed of several components. It is precisely these different components that mean that we have to nuance the answer somewhat, and therefore cannot simply represent it in black and white.

Strictly speaking, there is only a part of the ostrich egg that meets one of the above terms, namely the yolk. What we refer to as the yolk or yolk of the egg (but in fact the whole thing wrapped in the yolk membrane) is nothing more or nothing less than a single cell.

The ‘yellow of the egg’ in birds and reptiles is nothing more than the egg cell, crammed with nutrients, which is supposed to be fertilized by a sperm cell shortly after ovulation to grow into a new organism, consisting of different organs, .. .

Since this is an unfertilized egg and this entire development does not continue, the yellow of the egg remains that one single cell.

However, an (ostrich) egg is more than egg yolk. However, all the layers surrounding the yolk, such as the egg white, the shell membranes, the egg shell,… are secretions of the cells of the fallopian tube through which the egg cell passes on its way out. Body secretions, just like saliva, mucus, sweat,… are cellless substances and are therefore not included in one of the terms mentioned above. So you can simply ignore them in this question, so that the actual question was purely about the egg yolk and therefore the unfertilized egg…