Cell Division: Meiosis – Biology Poster, 36×26
by American Educational Products

We all start out life as a zygote that was formed by the fusion of a sperm nucleus and an egg nucleus. Over the course of gestation, the cells that make up the zygote divide at an astronomical rate, causing it to grow in size and complexity. As meiosis progresses, each new cell gets the same number and kind of chromosome found within the parent cell. The higher the “species number”, or number of chromosomes, the more complex it is to track meiosis.

This poster uses the Ascaris, a parasitic worm, to illustrate meiosis, because the chromosomes are relatively large compared to others, making them easier to see. It also only has 4 chromosomes, or 2 pairs, making it extremely easy to follow along as meiosis occurs, compared to using a human as an example, with its 23 pairs.

Each slide features extremely thin cross-sections of Ascaris oocytes, each one carefully selected to clearly illustrate the important processes that are occurring at different points. Bear in mind however, that these are just slides, and not the whole cell, so there will be other things happening that are not visible in the photograph.