18 sept. 2014ferns&moss.ppt1 ferns & mosses spore dispersed plants

18 Sept. 2014 Ferns&Moss.ppt 1

FERNS & MOSSES

Spore Dispersed Plants


Spore-dispersed plants• Seedless, dispersion by spores• Advantages of spores

• Cheap, each one small, requires small resource investment

• Produced in huge numbers

• Can result in huge numbers of offspring

• Disadvantage

• Wasteful, most spores unsuccessful

• Must land on good moist soil

• Little resource to support growing gametophyte


Spore-dispersed vascular plants

• Vascular tissues, = xylem, phloem• Allow growth to large size

• Local ferns, horsetails, club mosses not very large, fronds 30-40 cm

• Tree ferns (tropical) to 18 m tall w/ fronds 3 m long

• Prehistoric club mosses tree-sized


Phylum Pterophyta (Ferns)

Phylum Pterophyta (Ferns)

• Leafy fronds, usually compound

• Fronds grow as “fiddleheads”


Phylum Pterophyta (Ferns)• Sporangia in sori

under fronds • One kind of spores

only homosporous

• Gametophyte with both antheridia & archegonia Antheridia release

sperm before archegonia mature!



Phylum Sphenophyta("horsetails" or "scouring rushes")

• Hollow, segmented stems• Minute bristle-like gray-brown fronds• Stems hard, gritty with crystals of silica

(SiO2, sand, glass)

Phylum Sphenophyta

• Sporangia at tips of stems in strobilus

• Heterosporous, two kinds of spores separate male &

female gametophytes.

• One living genus Equisetum



Phylum Lycophyta("club mosses" or "ground pine")

• Short stems with microphylls, one vein per leaf (veins don’t branch)

• Sporangia at tips of stems or axils of fronds in strobilus

• Heterosporous, two kinds of spores separate male & female gametophytes.


Phylum Lycophyta("club mosses" or "ground pine")


Spore-dispersed nonvascular plants

• Lack xylem or phloem Limited ability to transport water, minerals,

sugars

• Usually live in moist places Some can endure drying, metabolism

ceases until they are wet again.


Phylum Bryophyta(Mosses)

• Familiar, low green soft masses on ground, usually in moist places


Phylum Bryophyta(Mosses)

• Life Cycle (very different from ferns, etc.)dominant GAMETOPHYTE (haploid)

• familiar form

• green, with tiny leaf-like blades,

• antheridia & archegonia at top of mosszygote grows into SPOROPHYTE (diploid)

• = stalk + capsule

• Capsule dries, splits open, releases spores

• Spores grow into GAMETOPHYTE


Moss Life Cycle


Economic uses of ferns, mosses

• Horticulture, landscaping

• Peat moss (Sphagnum) soil conditioner, holds moisture, cut, dried, burned as fuel in Ireland,

Scandinavia.


Formation of a peat bog

• Continental glacier plows up soil• Glacier breaks up as it melts back


Formation of a peat bog

• Hole left fills with meltwater• Sphagnum grows from edges, may

eventually fill bog

Peat bog• Sphagnum • Spruce & Birch • Pitcher plants


Economic uses of ferns, mosses


• Carboniferous Period (middle Paleozoic) Ferns, tree ferns, tree-like

"horsetails," tree-like lycophytes fossilized

Coal deposits Power for heavy industry,

electrical generation


Origins of plants

• from some green algae • multicellular

• same photosynthetic pigments, chlorophyll a, b

• store food as starch

• cellulose cell walls

• alternation of generations


Evolution of plants

• One group includes Bryophyta (mosses) Gametophyte dominant

• 2nd group includes ferns & seed plants, Lycophyta—Coniferophyta Sporophyte dominant Vascular tissue


Evolution of plants• One group includes mosses, hornworts

dominant gametophyte, non-vascular

• 2nd group includes ferns, seed plants dominant sporophyte, vascular tissue


Challenges to terrestrial organisms (& how plants meet the challenges):

• 1. Getting water, water transport to cells• specialized vascular tissues

• 2. Evaporation, drying• waxes, oils in "epidermis," close stomata

• 3. Gravity, need for support• fluid pressure in vascular tissue;• lignified xylem = wood

• 4. Rapid temperature changes• evaporative cooling requires even more water!• seasonal: drop leaves or close stomata

18 sept. 2014ferns&moss.ppt1 ferns & mosses spore dispersed plants

Documents

bog slide

glass slide

ppt5 slide

ppt8 slide

ppt18 slide

ppt6 slide

ground pine slide

growing gametophyte