Review of Plant Diversity

Bryophytesnon-vascularland plants

Pteridophytesseedless vascular plants

Gymnospermpollen & “naked” seeds

Angiospermflowers & fruit

pollen & seeds

vascular system = water conduction

mosses ferns

conifersflowering plants

colonization of land

Ancestral Protist

flowers

diploidmulticellularsporophyte2n

haploidmulticellulargametophyte1n

gametes1n

Plant

alternation of generations

mitosismitosis

fertilization

mitosis

meiosis

spores1n

zygote 2n

A Review of Alternation of Generations…

How is this different from animal life cycles?

A Gametophyte is:

A Sporophyte is:

First land plantsBryophytes: mosses & liverworts

non-vascularno water transport systemno true roots

cuticle prevents drying out

swimming spermflagellated sperm

lifecycle dominated by haploid gametophyte stagefuzzy moss plant you are

familiar with is haploid

spores for reproduction

diploidhaploid

Where mustmosses live?

Why can’t mosses grow

large?

Bryophytes: mosses & liverworts

Liverwort

Moss

Peat Bog

“Peat Moss”

Bryophyte significanceFood for mammals and birds

Prevent soil erosion along streams

Commercially – peat moss (Sphagnum) is used as a fuel, a soil conditioner, and by florists

FERNSSelaginella Psilotum

Horsetails Ferns

An important group of plants – 10,000 species exist!

First vascular plantsPteridophytes: ferns

vascularwater transport systemxylem, phloem, roots,

leavesswimming sperm

flagellated spermlife cycle dominated by

sporophyte stageleafy fern plant you are

familiar with is diploidfragile independent

gametophyte (prothallus)spores for reproduction

haploid cells which sprout to form gametophyte

diploid

Where mustferns live?

haploid

Alternation of generationsFern gametophyte (1n)

small haploid plant which produces gametes

archegonia

antheridia

diploid

Alternation of generations

haploid

produces male & female gametes

archegonia

antheridia

Fern sporophyte body partsFern sporophyte

has fronds (leaves)

• Young fronds are called fiddleheads• They also have an underground horizontal stem called the rhizome

• True roots come from the rhizome

Rhizome

FrondsUnder the fronds, spores are

produced in sporangia in clusterscalled sori (sorus = singular)

Spores grow into the gametophyte

The gametophyte grows the sporophyteThe sporophyte makes more spores

Significance of fernsEcologically important: Hold and form soil to

prevent erosion

As food – fern fiddleheadseaten in Hawaii, Japan, Philippines – very nutritiousand delicious!

As ornamental plants

Coal formationfrom ancient ferns

Early Pteridophytes: Tree Ferns

Carboniferous forest – 290-350 myaForests of seedless plants decayed into deposits of coal & oil

Pteridophytes: Tree fernsfrondsfrondsfiddleheadsfiddleheads

More seedless vascular plants… Club Moss

Horsetail

What next…?What major problems do bryophytes and

pteridophytes face?

What features do more advanced plants have that deal with these problems?