Gymnosperm & Angiosperm - Explore Biology

26 Pages·2005·1.44 MB·English

Gymnosperm
& Angiosperm
Rise of the
seed plants
AP Biology 2004-2005
27
Gymnosperm: conifers
 Characteristics
vascular

heterospory

 male vs. female gametophytes
seeds

 naked seeds (no fruit)
pollen

 contain male gametophyte
life cycle dominated by sporophyte stage

 coniferous trees you are familiar with are diploid
 reduced (microscopic) gametophyte
 reduction of gametophyte protects delicate egg
& embryo in protective sporophyte
 protected from drought & UV radiation
AP Biology 2004-2005
28
Evolutionary trends in land plants
 Reduction in gametophyte
gymnosperm
bryophytes pteridophytes
angiosperm
AP Biology 2004-2005
29
Early Gymnosperm: ginkgo
AP Biology 2004-2005
30
Early Gymnosperm: cycads
AP Biology 2004-2005
31
Gymnosperm: conifers
AP Biology 2004-2005
32
Cones & naked seeds
AP Biology 2004-2005
33
Gymnosperm (Pine) life cycle
female
gametophyte
in cone
meiosis meiosis
male
gametophyte
in pollen
f e r t ili z a t i o n
sporophyte
in seed
AP Biology 2004-2005
34
sporangium & pollen
male
male (pollen) cones
female
female cones pine embryo
AP Biology 2004-2005
35
Angiosperm: flowering plants
 Characteristics
vascular

heterospory

 male vs. female gametophytes
flower

 specialized structure for sexual reproduction
seeds within fruit

pollen

life cycle dominated by

sporophyte stage
 trees & bushes you are familiar
with are diploid
 reduced (microscopic)
gametophyte
AP Biology 2004-2005
36