The important difference between Mitosis and Meiosis I is that homologus chromosomes pair with each other in Meiosis and Crossing over occurs.
Early Prophase I- Leptonema- Extended Chromosomes condense and become visible as long thin threads. once here a cell is comitted to meiosis.
Middle Prophase I - Zygonema- Chromosomes align and form a synapsis and synaptomeal complex.
Middle Prophase I- Pachynema- Crossing over occurs if the chromosomes are different they produce a recombinant chromosome. (most important step in genetics)
Late Prophase I- Diplonema- the synaptonemal Complex disassembles and the results of crossing over form a x called a chiasma and they move apart.
Later Prophase I- Diakinesis- The chromosomes condense even more, and the 4 members of the tetrads become visible.