Life Cycle of a Gymnosperm

Life Cycle of a Gymnosperm - A Closer Look at the Life...

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Unformatted text preview: A Closer Look at the Life Cycle of a Gymnosperm • 1. 2. 3. Key features of the gymnosperm life cycle include Dominance of the sporophyte generation The role of pollen in transferring sperm to ovules No water required The development of seeds from fertilized ovules Pine Life cycle - Figur e 3 0. 6 Co nc p e t 3 0. 3: Th e r e pr o d u c tiv e a d a p a t a tio n s of a n gio s p e r m s inclu d e flow e r s a n d fruit s • Angio s p e r m s , a . k. a ., flow e rin g pl a n t s – “c ov er e d s e e d s ” • D eriv e d tr ait s a r e t h e r e pr o d u c tiv e s tr u c t ur e s c all e d flow e r s a n d fruit s • Th e m o s t wid e s pr e a d a n d div e r s e of all pl a n t s - 2 5 0, 0 0 0 s p e ci e s - 9 0 % of all e x t a n t s pl a n t s p e ci e s Angio s p e r m Div er sity Figur e 3 0. 1 2 Fro m figur e 3 0. 1 3 Flow e r s • • Fruit s • • A m a t ur e ov a r y Ov a r y m a t ur e s af t e r fertiliz a tio n of o v ul e s Ca n b e c arri e d b y win d, w a t e r, or a ni m al s, e n h a n ci n g di s p e r s al S p e ci aliz e d for s e x u al r e pr o d u c tio n S p e ci aliz e d s h o o t wit h m o difie d le a v e s S e p al s: e n clo s e t h e flow e r Pe t al s: brig h tly c olor e d, a t t r a c t p ollin a t or s St a m e n s : pr o d u c e p oll e n Car p el s: pr o d u c e ov ul e s Th e Angios p e r m Life Cycl e • Do u bl e fer tiliz a tio n o c c u r s w h e n a p oll e n t u b e di s c h a r g e s 2 s p e r m int o t h e g a m e t o p h w / in a n ov ul e - 1st sperm combines w./ 2 nuclei in the center cell of the gametophyte & initiates development of endosperm • Endosperm nourishes the developing embryo Angiosperm Life Cycle Figure 30.10 Gymnosperms and angiosperms have the following traits in common except ovaries With respect to angiosperms, which of the following is incorrectly paired with its chromosome count? Egg cell-n Megaspore-2n (going to be haploid) Microsporocyte-2n Endosperm-3n One difference between gymnosperms and angiosperms is that 1. Only angiosperms reproduce sexually 2. Only angiosperms produce fruits 3. Only angiosperms produce seeds 4. Only angiosperms produce wood . ...
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