Transcript Document

THE PLANT KINGDOM
All Plants Evolved from
Common Ancestor: Ancient
Green Algae




Cell walls made of cellulose
Store excess carbohydrates as starch
Form a cell plate during cytokinesis
Have same photosynthetic pigments:
 Chlorophyll a and b
 Carotenoid – carotene and xanthophyll
Adaptations to life on
land:
 Cuticle
 Waxy layer on aerial portion that prevents
dessication
 Thickness depends on how dry the
environment is
Adaptations to life on
land:
 Cuticle
 Stomata:
 Pores on the surface of leaves and stems
 Allows for gas exchange
Adaptations to life on
land:
 Cuticle
 Stomata
 Gametangia
 Multicellular sex organs
 Covered by a layer of sterile cells –
protection
 Embryo develops inside gametangia
Plant Life Cycle

Alternation of
generations

Gametophyte



Multicellular haploid
stage
Produces gametes
Sporophyte


Multicellular diploid
stage
Produces spores
Gametophyte generation

Gives rise to haploid gametes by mitosis

Sperm cells form in antheridia

Egg cells form in archegonia

Once sperm cell fertilizes an egg cell, a zygote
is formed
Sporophyte generation

Begins with diploid zygote

Zygote divides by mitosis and develops into
embryo

Grows into mature sporophyte plant

Specialized cells called sporogenous cells
divide by meiosis into haploid spores
Four Main Groups of Plants

Bryophytes

Seedless vascular
plants

Gymnosperms

Angiosperms
Bryophytes





Nonvascular plants
Rely on diffusion and osmosis
Restricted in size
Generally require moist environment
MOSSES, LIVERWORTS, HORNWORTS
Moss Life Cycle
Vascular Plants

Ferns, Gymnosperms, Angiosperms

Contain xylem and phloem

Cell walls contain lignin
Strengthening polymer
 Support
 Conduction
 Allows plants to grow tall

Seedless Vascular Plants

Ferns & club mosses

Most important adaptation:
Xylem – transports water
 Phloem – transports food


Transport allows plants to grow larger
Club Mosses

Only group of vascular plants with microphyll




Leaf with single vascular strand
True Roots
Rhizome & aerial stems
Reproductive leaves with sporangia
Ferns

Rhizome w/ roots

Fronds

Sori found on fronds
Clusters of sporangia
 Sporagenous cells undergo meiosis  spores

Fern Life Cycle
Prothallus
Homospory vs. Heterospory


Homospory – sporophyte produces 1 kind of
spore
Heterospory – microspores & megaspores
Dominant Stages

Bryophyte – Gametophyte

Seedless Vascular – Sporophyte

Gymnosperms – Sporophyte

Angiosperms - Sporophyte