G on the scales of pine cones 850 species angiosperms

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Unformatted text preview: within megagametophyte Living seed plants Gymnosperms:   “Naked seeds”   Produce seeds that are totally exposed and found, e.g., on the scales of pine cones   ~850 species Angiosperms: “Hidden seeds”   Closed carpels enclosing ovule(s)   Flowers   Endosperm (double fer�liza�on)   > 250,000 species Ovule (gymnosperm) Living seed plants Phyla: Coniferophyta: Conifers Cycadophyta: Cycads Ginkgophyta: Ginkgo Gymnosperms Gnetophyta: Ephedra, Gnetum, Welwitschia Magnoliophyta: flowering plants Angiosperms 3 Seed plant rela�onships Seed plant rela�onships Conflic�ng phylogene�c hypotheses Conflic�ng phylogene�c hypotheses Fossil, morphological, molecular evidence -­‐ What’s up with the Gnetophytes? Seed plant rela�onships New evidence: a phylogenomic approach Gymnosperms Some ex�nct gymnosperms:   Seed “ferns” – diverse “group”   Cordaitales – primi�ve conifer-­‐like   Caytoniales – ovule enclosed by a cupule (partly fused leaf-­‐like structures)   Benne�tales – resembled modern cycads; strobili (cones) similar to magnolia flower   Close rela�ves of angiosperms? Bennettitales “flower” Cibrián-­‐Jaramillo et al. 2010. Genome Biol. Evol. 2:225-­‐239 [Lee et al. 2011. PLoS Gene�cs 7(12):e1002411] 4 Living gymnosperms Coniferophyta Conifers (~50 genera, 550 species) Cycadophyta Cycads (10-­‐12 genera, ~250 species) Conifers   Ecologically important: Occupy large areas of Earth   Dominant plants of boreal/high al�tude forests   Have large economic importance: –  Lumber/building materials, paper products, landscaping, Christmas trees, u�lity poles, furniture, flooring Ginkgophyta Ginkgo (1 species!) Gnetophyta Ephedra, Gnetum, Welwitschia (3 genera, 70 species) Conifers   Most species are trees; some shrubs, no herbs   Most species have persistent foliage ⇒ “evergreens”   Simple, needle/scale-­‐like leaves   Most have both male and female reproduc�ve parts on the same plant (pollen/seed cones)   Produce seeds within cones Conifers: Pine family (Pinaceae)   Most species-­‐rich conifer family   Most of Northern Hemisphere   11 genera, ca. 250 spp   Includes pine, spruce, fir, hemlock, larch (deciduous) Larch (Larix) Pine (Pinus) Fir (Abies) Spruce (Picea) 5 Other conifers: Cypress family (Cupressaceae) Conifers: Pine family (Pinaceae)   Most widely distributed conifer family   The leaves are arranged ei...
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This note was uploaded on 02/25/2014 for the course BIO 318 taught by Professor Maryabisson during the Spring '11 term at SUNY Buffalo.

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