• Cells undergoing?meiosis?can be observed and photographed using specialized microscopes
• The different stages of meiosis have distinctive characteristics meaning they can be identified from photomicrographs
• Being able to identify the stages of meiosis from photomicrographs and diagrams is an important skill for a biologist

Step 1: Identifying if meiosis I or meiosis II is occurring

• Homologous chromosomes?pair up side by side in meiosis I only
  • This means if there are?pairs of chromosomes?in a diagram or photomicrograph?meiosis I?must be occurring
• The?number of cells forming?can also help identify whether meiosis I or II is occurring
  • If there are?two new cells?forming it is?meiosis I?but if there are?four new cells?forming it is?meiosis II

Identifying which stage of meiosis I is occurring

• Prophase I:?Homologous pairs?of chromosomes are visible in diploid cell (2n). Crossing over occurs
• Metaphase I: Spindle fibres pull homologous pairs so they are lined up?side by side?along the?equator?of the cell. Orientation of homologous chromosomes is random
• Anaphase I:?Whole chromosomes?are being pulled to opposite?poles?with?centromeres intact
• Telophase I:?There are?2 groups?of condensed chromosomes around which nuclei membranes are forming
• Cytokinesis:?Cytoplasm is dividing and the?cell membrane is pinching inwards?to form?two cells?with haploid chromosome numbers (n)

Prophase I, Metaphase I , Anaphase I and Telophase I as seen in photomicrographs

Identifying which stage of meiosis II is occurring

• Prophase II:?Single whole chromosomes?are visible in haploid cells
• Metaphase II: Single whole chromosomes are lined up along the?equator?of the cell in a?single file
• Anaphase II:?Centromeres divide?and?chromatids?are being pulled to opposite?poles
• Telophase II:?Nuclei are forming around the?4 groups?of condensed chromosomes
• Cytokinesis: Cytoplasm is dividing and?four haploid cells?are forming

Prophase II, Metaphase II , Anaphase II and Telophase II as seen in photomicrographs

Drawing the stages of meiosis

• The distinguishing features mentioned above can also be used by biologists to draw scientific diagrams of meiosis I and meiosis II
• The conventions for drawing are:
  • The drawing must have a title
  • A?sharp HB pencil?should be used (and a good eraser!)
  • Drawings should be on plain white paper
  • Lines should be?clear,?single?lines?(no thick shading)
  • No shading
  • The drawing should take up as much of the space on the page as possible
  • Well-defined structures should be drawn
  • The drawing should be made with?proper proportions
  • Label lines?should not cross or have arrowheads and should?connect directly?to the part of the drawing being labelled

Drawing the different stages or phases of meiosis