How Plants Colonized Land

Page
6

Slide 35

Homosporous spore production

Sporangium

on sporophyll

Single

type of spore

Typically a

bisexual

gametophyte

Eggs

Sperm

Eggs

Sperm

Heterosporous spore production

Megasporangium

on megasporophyll

Megaspore

Female

gametophyte

Male

gametophyte

Microspore

Microsporangium

on microsporophyll

Slide 36

Seedless Vascular Plants

Lycophytes (Phylum Lycophyta)

Selaginella apoda,

a spike moss

Isoetes

gunnii,

a quillwort

Strobili

(clusters of

sporophylls)

2.5 cm

Diphasiastrum tristachyum, a club moss

1 cm

Slide 37

Seedless Vascular Plants

Pterophytes (Phylum Pterophyta)

Athyrium

filix-femina,

lady fern

Vegetative stem

Strobilus on

fertile stem

1.5 cm

25 cm

2.5 cm

Psilotum

nudum,

a whisk

fern

Equisetum

arvense,

field

horsetail

Slide 38

The Significance of Seedless Vascular Plants

Increased photosynthesis may have helped produce the global cooling at the end of the Carboniferous period.

The decaying plants of these Carboniferous forests eventually became coal = fossil fuel.

Slide 39

Artist’s depiction of a Carboniferous forest based on fossil evidence

Slide 40

Derived Traits of Plants

Gametophyte

Mitosis

Mitosis

Spore

Gamete

Mitosis

n

n

n

n

2n

MEIOSIS

FERTILIZATION

Zygote

Sporophyte

Haploid

Diploid

1

2

3

4

Alternation of generations

Apical meristems

Multicellular gametangia

Walled spores in sporangia

Archegonium

with egg

Antheridium

with sperm

Sporangium

Spores

Apical meristem

of shoot

Developing

leaves

Slide 41

You should now be able to:

Describe four shared characteristics and four distinct characteristics between charophytes and land plants.

Diagram and label the life cycle of a bryophyte

Explain why most bryophytes grow close to the ground and are restricted to periodically moist environments.

Describe three traits that characterize modern vascular plants and explain how these traits have contributed to success on land.

Slide 42