Meiosis

Meiosis I

Prophase I

Condensation of chromosomes

Disintegration of nuclear envelope and nucleolus

Homologous chromosomes pair up (synapsis)

Chiasmata observed

Metaphase I

bivalents arrange at the equator

arrangement of each bivalent is completely independent of the other.

Attachment of chromosomes to spindle fibers

Anaphase I

Separation of homologous chromosomes

one of the pair pulled to one pole, and the other to the other pole

Telophase I

Chromosomes reach opposite poles of the spindle

Spindle fibres disintegrate

Nuclear envelope surrounds each group of chromosomes

Each daughter nucleus has half the chromosome number as the parent nucleus.

Meiosis II

Prophase II

disintegration of nucleolus and nuclear envelope

movement of centrioles to opposite poles

spindle fibers develop at right angles to the spindle axis of meiosis I

Metaphase II

Chromosomes arrange themselves at the equator

Attachment of chromosomes to spindle fibre

Anaphase II

Centromeres divide

Chromatids are pulled to opposite poles

Chromotids become the chromosomes of the daughter cells

Teophase II

Chromosome uncoil and become indistinct

Spindle disintegrates

Nuclear envelope and nucleolus reform

Four daughter cells

genetically different from parent cell

half the chromosome number of parent cell