Transcript Seedless Vascular Plants - Mr. Barrow's Science Center

SEEDLESS VASCULAR
PLANTS
Packet #70
Chapter #29
THE THEORY OF EVOLUTION
CONNECTION

Seedless vascular plants arose in the
Carboniferous Period 420 – 360 mya

Phylum Rhinophyta are known as the oldest seedless
vascular plants
These organisms left relics, fossils and coals
 Scientists believe that seed plants were present
during this evolutionary time period but were not
dominant.
 Seedless vascular plants became important as
the swamps dried up and the global climate
cooled.

TYPES OF SEEDLESS VASCULAR
PLANTS

There are four phyla of seedless vascular plants.

Phylum Polypodiophyta


Phylum Psilotophyta


Whisk ferns
Phylum Equisetophyta


Ferns
Horsetail
Phylum Lycophyta

Club Mosses
IMPORTANT INFORMATION
FOR VASCULAR PLANTS
LEAVES OF VASCULAR PLANTS
Leaves of Vascular Plants

There are two types of
leaves that may be found
on seedless vascular plants

Microphylls


Small and have a single
vascular strand
 Club mosses
Megaphylls


Larger and have more than
one vascular strand
Plants needed a flattened
blade with more stomata for
gas exchange
 Ferns, horsetails and
seed plants
Microphylls
KEYWORDS OF VASCULAR PLANTS

Homospory

The production of one
kind of spore
Bryophytes
 Whisk ferns
 Horsetails
 Most club mosses
 Most ferns


Spore gives rise to
gametophyte plants
that produce both egg
and sperm cells.
KEYWORDS OF VASCULAR PLANTS
II

Heterospory

Production of two kinds of
spores



Occurs in




Microspores
 Give rise to male
gametophytes that
produce sperm cells
Megaspores
 Give rise to female
gametophytes that
produce eggs.
Certain club mosses
Certain ferns
ALL SEED PLANTS.
The “evolution” of
heterospory was an
essential step in the
evolution of seeds.
SEED VASCULAR PLANTS—
FERNS
PHYLUM PTEROPHYTA
SUBPHYLUM POLYPOIOPHYTA
THE FERNS

Largest and most
diverse group of
seedless vascular
plants.

Have xylem and
phloem tissue
Most have true roots
 More than 12,000
species have been
described.

PHYLUM PTEROPHYTA
SUBPHYLUM POLYPOIOPHYTA
THE FERNS
Almost all species are
homosporous
 All have megaphylls.
 Found primarily in
moist tropical habitats


Few are aquatic
FERNS
FEATURES THAT DISTINGUISH FERNS AND
OTHER SEEDLESS VASCULAR PLANTS FROM
ALGAE AND BRYOPHYTES.

Comparison to
Bryophytes
Ferns have vascular
tissue
 Ferns have a
dominant sporophyte
generation.
 As in bryophytes,
reproduction in ferns
depends on water as a
transport medium for
their motile sperm
cells.

REPRODUCTIVE CYCLE OF
FERNS
PHYLUM PTEROPHYTA
SUBPHYLUM POLYPOIOPHYTA
THE FERNS
Figure 29.12
Page 585
Ferns display
alternation of
generation and they
have a dominant
sporophyte
generation
 Fern bodies consist of
a rhizome (an
underground stem),
roots, and leaves
(megaphylls).

PHYLUM PTEROPHYTA
SUBPHYLUM POLYPOIOPHYTA
THE FERNS
Sprophytes have
roots, rhizomes and
leaves that are
megaphylls.
 Leaves, or fronds,
bear sporangia in
clusters called sori.
 Meiosis of sporangia
produces haploid
spores.

PHYLUM PTEROPHYTA
SUBPHYLUM POLYPOIOPHYTA
THE FERNS

Spore germinates and
grow via mitosis into a
gametophyte called
haploid prothallus.





Heart shaped and lacks
vascular tissue
Anchored by rhizoids
Bears antheridia and
archegonia
Water is still required for
transportation of the
flagellated sperm to the
archegonium
Zygote grows into freeliving sporophyte plant.
SEEDLESS VASCULAR
PLANTS—WHISK FERNS
PHYLUM PTEROPHYTA
SUBPHYLUM PSILOTOPHYTA
THE WHISK FERNS
Simplest vascular
plants
 Lack true roots and
leaves
 Consists of
dichotomously
branching rhizomes
 Have erect stems.
 Homosporous
sporophylls.

SEEDLESS VASCULAR
PLANTS—HORSETAILS
PHYLUM PTEROPHYTA
SUBPHYLUM EQUISETOPHYTA
THE HORSETAILS
Sporophytes have
roots
 Rhizomes
 Aerial stems



Hollow and jointed
Leaves that are
reduced megaphylls
SEEDLESS VASCULAR
PLANTS—CLUB MOSSES
PHYLUM LYCOPHYTA
THE CLUB MOSSES
Small plants with
rhizomes and short
erect branches
 Extant species have
true roots and leaves
that are microphylls.

REVIEW
REVIEW

Students

List potential examination questions and/or here, and
on following slides, based on the packet.