Lecture 9

Lecture 9 - Lecture 9 Evolution of Seed Plants Plant...

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Lecture 9 Evolution of Seed Plants Plant Diversity 2 6-23-09 Evolu of seed plants -origin 360 ma seed: an embyro and its food supply surrounded by a protective coat -enromous empact of human society aggi around 13,000 years ago transition from hunter-gathers to permanent Living lineages Gymnosperms 800 species -Ginko 1 species -Cycads Gnetophytoes conifers Angiosperms 250,000 species -most widespread and diverse plant group, 90% of all plants belong traits common 1. Reduced gametophytoes gametophyties develp within walls of spores that are rtetained within tissues of the plant sporophyte -protects female from environmental stress -game able to obtain nutrients from parent sporophyte Advantages of heterospory -sets stage for formation of seed allowed for retention of egg allowed for dispersal of pollen mega-female micro-male Ovules and production of eggs -ovule consists of megasporangium Pollen and production of sperm microspores develop into pollen grains -contain male pollen grain germinates -pollen tube and 2 sperm advantages -eliminates dependency on water -greater dispersal
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This note was uploaded on 04/14/2010 for the course BIO 88509 taught by Professor Hagen during the Spring '10 term at Kansas.

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Lecture 9 - Lecture 9 Evolution of Seed Plants Plant...

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