Pollen (microsporocyte, pollen mother cell or meiocyte), after meiotic division. After the formation of the four microspores, which are contained by callose walls, the development of the pollen grain walls begins. The callose wall is broken down by an enzyme called callase and the freed pollen grains grow in size and develop their characteristic shape and form a resistant outer wall called the exine and an inner wall called the intine. The exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive. In simultaneous microsporogenesis meiotic steps I and II are completed
Development of Spore pack has been revealed so far, called "galactic adventures" . It will include an adventure editor, as well as many new items and the ability for a player to go down to a planet's surface. On June 24, 2008, the "Spore: Galactic Edition" was announced. This special edition game is priced at $79.99, and includes a "Making of Spore" DVD video, a "How to Build a Better Being" DVD video, by National Geographic Channel (not included in all countries), a "The Art of Spore" hardback mini-book, a fold-out "Spore" poster and a 100-page Galactic Handbook. "Spore" extensively uses procedural generation,