BIOL-4717EL Lecture Notes - Lecture 4: Cycad, Gnetophyta, Gymnosperm
4 Mar 2019
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The gametophyte became more reduced than in the ferns to their seedless vascular plants. Pollination replaced swimming as the mechanism for delivering sperm nuclei to the egg. The seed evolved instead of the zygote developing directly into young sporophyte. The zygote of a seed plant develops into an embryo, that is packaged along with food supply within a seed coat. Gymnosperms (read the life cycle of pines from the textbook. The name conifer comes from the reproductive structure of these plants, the corn. Pines, fir, spruce, larches, junipers, cedar, red 2wood. Conifers dominate vast regions of northern hemisphere representing a large source of wood and paper pulps. Nearly all conifers are evergreen - the needle shaped leaves of pines are adapted. This phylum is represented by only one extant species - it has fan like leaves that turn gold color in autumn and the plant is deciduous - dioecious (the female tree and male are seperated)
