BIOL 1202 : Bio Exam 3 Notes
Document Summary
Chapter 30: plant diversity ii: the evolution of seed. 30. 1 seeds and pollen grains are key adaptations for life on land. Characteristics common to all seed plants: seeds, reduced gametophytes, heterospory, ovules, pollen. Gametophyte/sporophyte relationships: gametophytes of seed plants develop within the walls of spores. Figure 30. 2 retained within tissues of the parent sporophyte: no longer dependent on water for fertilization. Ovules and productions of eggs: an ovule consists of a megasporanguim, megaspore, and protective integuments. Pollen and production of sperm: microspores develop into pollen grains, contain male gametophyte, pollen can be dispersed by air or animals, eliminates the need for water in fertilization (picture of microsporangia, pine pollen, and angiosperm pollen grains) If a pollen grain germinates, : it gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule. A seed: develops from the whole ovule, includes sporophyte embryo, food supply, protective coat. 30. 2 gymnosperms bear naked seeds, typically on cones.