Animal oocytes undergo the most extremely asymmetric divisions in the animal world.  Oocytes are typically required to grow large enough to contain the fuel, the ribosomes,  the mitochondria and other materials required to complete embryogenesis – whatever it takes to make a functional animal or larva that can feed itself.  (We placental mammals are an exception; our smallish oocytes only carry enough supplies to get to implantation.)  Perhaps to help them get so big, oocytes keep around not just two but four copies of each chromosome until they’re fully grown, then dispose of three of the four copies through meiosis to become an egg (the haploid female gamete).  In most oocytes, meiosis creates polar bodies – cells that are just big enough to hold a discarded nucleus, and hardly any cytoplasm or organelles if the oocyte can help it – that remain associated with the egg, and by definition mark the so-called animal pole.  The polar bodies have no future, and their sole known  function is to tell developmental biologists which way is up.

Meiotic divisions in the oocyte have a lot in common with mitosis, including the fundamental cytokinetic rule that the cleavage furrow crosses the midplane of the spindle to partition the two separated sets of chromosomes.  In this video of first meiosis in a starfish oocyte, a wave of actin disassembly sweeps across the oocyte surface, followed immediately by a wave of new assembly.  The wave seems to break at the spindle midzone, such that an actin-depleted zone overlies the spindle; a tiny bud forms containing half the spindle and one complete set of chromosomes. 

— text by George von Dassow