BIOL 2P93 Lecture Notes - Lecture 27: Tracheid, Herbaceous Plant, Amborella
24 Jan 2016
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Document Summary
Angiosperm ancestors: transformation of ovule-bearing structures of gymnosperms into a carpel = important, cladistics defined major natural groups of seed plants + understand interrelationships btwn by fossil, morphological + molecular data. Link btwn seed-bearing organs of caytoniales (mesozoic seed ferns) + angiosperm carpels. Order seen in triassic period + extinct end of cretaceous) are considered angiosperm ancestor. Wielandiella (bennettitales genus) thought to have flowerlike bisexual strobili (now rejected), now described having branched axes bearing leaves, immature seed cones, + flowerlike reproductive structures (pott, 2014), characteristics similar to extant angiosperms. Anthophyte hypothesis: gnetophytes were closest to angiosperms but molecular data doubted this showing gnetophytes nested w/in gymnosperms = angiosperms don"t have close relatives from living gymnosperms. Derived traits of angiosperms - reproductive structures + processes. Seed production: primary means of reproduction + dispersal. The flower: co-evolved w/ pollinators, lure insects, birds + bats for this purpose, increased diversity of flowering plants.
