29.1
How Did Seed Plants Become Today’s
Dominant Vegetation? 631
Features of the seed plant life cycle
protect gametes and embryos 631
The seed is a complex, well-protected
package 633
A change in anatomy enabled seed plants
to grow to great heights 634
29.2 What Are
the Major Groups of Gymnosperms? 634
The relationship between gnetophytes
and conifers is a subject of continuing
research 635
Conifers have cones but no motile
gametes 636
29.3
What Features Distinguish the Angiosperms?
638
The sexual structures of angiosperms
are flowers 638
Flower structure has evolved over
time 640
Angiosperms have coevolved with animals
641
The angiosperm life cycle features
double fertilization 642
Angiosperms produce fruits 643 29.4
How Did the Angiosperms Originate
and Diversify? 645
The basal angiosperm clade is a matter
of controversy 645
The origin of the angiosperms remains
a mystery 646 29.5
How Do Plants Support Our World? 647
Seed plants are our primary food source
647
Seed plants have been sources of medicines
since ancient times 647
