Glossary of terms relating to reproduction and meiosis:

Crossing over -

The exchange of genetic material between homologous chromosomes during the first stage of meiosis. It results in genetic variation in populations greater than that which might result from independent assortment alone.

Daughter cell -

A cell which results from division of another cell (a mother cell), either in meiosis or mitosis.

Diploid -

A cell with two copies (and only two) of each of its chromosomes.

Embryo -

The stage of an organism's development in which tissues and organs develop beginning with a fertilized zygote.

Gamete -

In animals, a haploid cell which results from the second stage of meiosis. In plants, the haploid cells proceed through an intermediate, multicellular stage before producing gametes. Male gametes are sperm; female gametes are eggs.

Haploid -

A cell with only a single copy of each chromosome.

Homologous chromosomes -

Chromosome pairs within cells which have the same sequences of genes. One chromosome of each pair comes from each of the parents through its gamete.

Independent assortment-

The random arrangement and partitioning of homologous chromosomes during the first cell division stage of meiosis.

Meiosis -

A two stage process of cell division which results in four daughter cells, each having only half the number of chromosomes as the mother cell.

Zygote -

The fused egg and sperm; the result of fertilization. In humans, this is also called the pre-embryo and the term is applied to the dividing cells during the first two weeks of development.