BIOL 2004 Lecture 7: Phylum Coniferophyta (end) & Angiosperms

• School: Dalhousie University
• Department: Biology
• Course: BIOL 2004
• Professor: Gunawardena Arunika

Document Summary

Lecture 7 - phylum coniferophyta (end) & angiosperms. The only living species = ginkgo biloba: must know this name. Living ginkos seem unchanged from ginko fossils that are 150 million years old. Megagametophyte gives rise to fleshy seeds that look like small plums: not fruits, so-called fruits are anatomically different from true fruits in angiosperms, flesh is a seed coat, rather than an ovary surrounding a seed. Like cycads and gnetophytes, ginko has separate pollen and seed-producing plants. Includes 70 species, divided into three genera: ephedra, gnetum, welwitschia. Each gnetophyte species has separate pollen and seed-producing plants - excluding ephedra. Three genera differ distinctly but are categorized together because of molecular evidence - they have more angiosperm-like features than other gymnosperms. Presence of vessel elements in addition to tracheids. Welwitschia and gnetum - similar to flowering plants, do not have an archegonia.