chapter 25- seedless plants

plants share a common ancestor

green algae (charophytes) in archeaplastida supergroup of eukaryotes

Chlorophytes, Charophytes, and plants share

multicells, cell walls with cellulose, chloroplasts with same pigment, storage is startch

advantages of moving to land for plants

CO2 was higher, light is higher, more minerals, no herbivores, no competition

risks of moving to land

no support in air, risk of desiccation for adults and gametes

land plant adaptations

alternation of generations, walled haploid spores, apical meristem tissue in roots, waxy cuticle to resist desiccation, mycorrhizae, and cell walls with lignin

charophyte life cycle

NOT alternation of generations only multicellular is haploid

walled haploid spores

dispersal through air, sporopollenin protects, made with sporangium,

multicellular gametangia

sperm protected with antheridium

eggs protected in

archegonium, fertilization is here forming zygote

apical meristems

continuously dividing cells, roots grow towards resources

waxy cuticle

controllable stomata for gas exchange

secondary metabolites

chemicals that deter, repel, or poison competitors, herbivores, or parasites

mycorrhizae

mutualism with fungi, water and nutrient absorption, before true roots

nonvascular seedless plants

bryophytes, first plants to exist out of the water

nonvascular seedless plants 3 groups

liverworts, hornworts, mosses

bryophytes characteristics

non woody, small ground cover plants, need water for reproduction, have rhizoids for attachment (no true roots)

bryophyte reproduction

haploid gametophyte is dominant (makes egg and flagellated sperm, largest part), diploid sporophyte (depends on gametophyte for food, grows in archegonium of gametophyte, and sporangium makes haploid spores)

moss (bryophyta)

most numerous, extreme environments, sporophyte grows from female gametophyte to get higher for spore dispersal

mosses importance

pioneer species in nutrient poor soil, primary producers in extreme environments

sphagnum

peat moss important for wetlands and harvested fuel

seedless vascular plants (SVP)

2 main groups- Lycophytes and Monilophytes

Lycophytes 3 groups

club mosses, quilworts, spike mosses

monilophytes 3 groups

whisk ferns, ferns, horsetails

SVP characteristics

branched sporophytes independent of gametophyte for nutrition, diploid sporophyte dominates, vascular system, true roots and true leaves

xylem

cells to move water and minerals (inner part)

phloem

cells to move sugars, amino acids, and other organic products (outer part)

microphylls leaves

only lycophytes have these, small spine leaves supported by single strand of vascular tissue, unbranched

megaphyll leaves

all other vascular plants, leaves with high branched system, greater photosynthetic productivity than microphylls

sporophylls

leaves to make sporangia

fern sporophylls

look like normal leaves but have sori that make spores on the underside

lycophyte sporophylls

modified into cone shape called strobilus

homosporous spore production (most SVP)

sporangium on sporophyll, single spore, bisexual gamete (egg or sperm)

heterosporous spore production (all seed plants and some SVP)

megasporangium, megaspore, female gametophyte, eggs for males, microsporangium, microspore, male gametophyte, sperm

lycophytes (club mosses and relatives)

small, tropical and temperate, strobili, homosporous for club moss, heterosporeous for quilworts and spike moss

whisk ferns

monilophytes, dichotomus branching, no true leaves/roots, homosporous, photosynthesis in stem

horsetails

monilophytes, jointed stems with tiny leaves, strobili, homosporous, photosynthesis in stems

ferns

monilophytes, most diverse, homosporous, large megaphylles, sori on underside of sporophylls, mostly understory or epipytes (grows on another plant)