The Plant Kingdom

Key Characteristics of Plants

• Multicellular

• Cell specialization

• Photosynthetic autotrophs

• Sessile

• Alternation of Generations– Sporophyte– gametophyte

Green algae gave rise to plants• Both use the same type

of chlorophyll and assessory pigments

• DNA analysis shows commonality

• Both store food as starch and have cell walls made of cellulose.

Evolutionary Relationship Between Plants and Green Algae

Adaptation to Land

• Lost supportive buoyancy of water

• No longer surrounded by water and nutrients.

• Variation in climate

• Roots or rootlike structures

• Cuticle

• Stomata

• Eventually…..– Vascular tissue– lignin

Requirements for Plants to Survive on Land

Without water, strategies for dipersal of sex cells needed to be

developed

• Sex cells and zygote needed a means of dispersal that was independent of water.

• Protective structures were required to protect the developing embryos.

• The above were achieved with the origin of the seed plants.

Characteristics• Nonvascular

• Lack true roots, leaves and stems

• Rootlike structure s are called rhizoids

• Rely on diffusion and poorly developed conducting tissues to distribute water and nutrients.

• Enclosed reproductive structures– Archegonia– Antheridia

Characteristics of Nonvascular Plants

Reproductive cycle for Bryophytes

Types of Nonvascular Plants

BRYOPHYTA

Hepatophytaliverwort

AnthocerophytaHornworts

Vascular Plants(tracheophytes)

• Conducting vessels also provide support.– Xylem– Phloem

Seedless Vascular Plants(reproduce via spores)

Types of Seedless Vascular Plants

PSILOPHTAwhisk ferns

• Epiphytes

• Rootless and leafless

LYCOPHYTAclub mosses

• Produces a sporangia bearing strobilus.

SPHENOPHYTAHorsetails

• Genus: Equisetum• Large deposits of

silica in their leaves.• Jointed stems with

whorled leaf arrangement.

SPHENOPHYTAHorsetails

PTEROPHYTATrue ferns

• Broad leaves called fronds

• Leaflets called pinnae

• Sporangium (sorus pl sori) are formed on the underside of the fronds.

• Unfolding fronds are called fiddleheads.

• Spores are dispersed by the wind.

PTEROPHYTATrue ferns

Fern reproductive life cycle

Seed producing plants

• Major adaptations– Pollen (male gametophyte)– Seeds (embryonic plant)

(male and female gametophyte are greatly reduced in size)

• Two types– Gymnosperms (lack flowers)– Angiosperms (flowering plants)

Characteristics of Vascular Plants With Seeds

Characteristics of Gymnosperms

CYCADOPHYTACycads

• Large fernlike leaves

• Plants are either male or female and produce gametes in large strobilus

CYCADOPHYTACycads

Ginkophyta

• Only one species in present day. Ginkgo biloba• Are resistant to air pollution• Bear male and female cones on separate plants.• Male produces pollen in strobilus-like cones.• Female bears seed which develop a fleshy

outer covering and resemble orange-yellow cherries. (Stinks!)

GINKGOPHYTAGinkgo biloba

CONIFEROPHYTACone-bearing trees

• Most diverse of the gymnosperms: produce seeds in woody cones. Include pine, fir, spruce, juniper, cedar, redwood, yew, and larch.

• Form large forests and have adapted to cold and dry habitat (taiga).

• Protected against water loss by leaves covered with a thick cuticle (cutin) and by covering it’s trunk and branches with bark.

• Conifers are evergreens– They do loose their leaves if aged or damaged.– Keeping leaves allows photosynthesis to begin at the earliest

moment in spring.• Found where nutrients are scarce as they eliminate need

to grow a whole new set of leaves (Deciduous trees lose their leaves).

Needles and Cones

Types of Gymnosperms

• CONIFEROPHYTA

• Cone-bearing trees

Life Cycle of a pine

GNETOPHYTA Can be found in the deserts or mountains of Asia, Africa

and central or South America. • 3 genera• 1. Gnetum : A tropical climbing plant• 2. Ephedra (Shrub-like plants and found in

U. S.)• i. “Mormon tea” Scrubby cone-bearing

plant with scale-like leaves.• a. Source of ephedrine: used to treat

asthma, emphysema, and hayfever.

• 3. Welwitschia (Desert dweller with large tuberous root)

• i. Has only 2 leaves and may live 100 yr.

Ephedra

Welwitschia

Life Cycle of Conifers

ANTHOPHYTAFlowering plants

Characteristics of Angiosperms

Types of Angiosperms

Floral Structure

Ovule Formation in an Angiosperm

Female reproduction

Parts of a Pollen Grain

Pollen Grain Formation

Male reproduction

Double fertilization

Seed Structure