BIO 2 Lecture 3: Bio_2_Wk_2_lecture_1_
Document Summary
Week 2: plant diversity iii & plant reproduction i. Name means naked seed (i. e. no fruits) 4 phyla (groups: cycads, ginkgo, gnetophytes, conifers. Water no longer required for reproduction: in some groups pollen tube carries sperm to egg cell, sperm no longer needs to swim to egg through water. Very numerous during mesozoic (~250 mya: typical plant associated with dinosaurs. 1 living species: ginkgo biloba, maidenhair tree, wild plants restricted to few small areas in china. Very resistant to air pollution: common in urban areas. Seed coat fleshy with a bad odor. Ephendra: familiar as herbal remedy, dietary supplement now banned in u. s. Welwitschia: coastal desert of angola, namibia, south africa, two strap leaves that grow forever, bio. ~630 species: gymnosperms you are most familiar with. Pines, firs, spruces, redwoods, larches, hemlocks, cypresses, junipers, yews: leaves often suited to low water availability, small group, but economically very important. Also very common during age of dinosaurs (up to 100 mya)
