LIFESCI 1 Lecture Notes - Lecture 9: Zygomycota, Carbon Cycle, Semipermeable Membrane
Document Summary
Number of species of ferns/horsetails dramatically declined: angiosperms probably occupied those niches, epiphytic ferns actually increased though. Most angiosperms are dicots rather than monocots. Female: carpel: stigma (sticky), style, ovary (contains ovules) Particular genes prevent self-fertilization: not able to biochemically and physically. Stigma is up higher than anther so pollen doesn"t stick to stigma. Male anther produces pollen that are protected from drying out. Gametophyte is dependent on sporophyte delivered through animal. Pollen grain has nucleus that produces pollen tube that connects pollen from stigma to ovule down in ovary. Ovule down in ovary connects pollen tube to egg in ovary where it is fertilized. Embryo is produced (baby plant) and is surrounded by endosperm (triploid material). Interaction between pollen grain and ovule (double fertilization: which gamete will make it to ovule (competition), within pollen there are two sperms. One of the sperm fuses with the egg and forms diploid zygote (2n).
