chapter 25: plant evolution

shared traits with green algae

photosynthesis, cellulose cell walls, chlorophyll pigments a & b, common sperm structure, starch storage

apical meristem

growing tips where cell division occurs; produce 3d tissue with low surface area:volume ration; prevent dessiccation

sporopollenin

resistant polymer encasing spores and pollen; prevent dessiccation and decay

gametangia

structures enclosing and protecting gametes

antheridia

male gametangia producing eggs via mitosis

archegonia

female gametangia producing eggs via mitosis

tracheophytes

have vascular tissue

cuticle

waxy coating; prevent water loss

stomata

regulated openings for gas exchange

xylem

conduct water and minerals upward; reinforced with lignin

phloem

conduct organic nutrients throughout plant

bryophytes

nonvascular; gametophyte dominant

seedless vascular

sporophyte dominant

gymnosperms and angiosperms

sporophyte dominant

bryophyte phyla

liverworts, moss, hornworts

seedless vascular phyla

lycophytes, pteridophytes

gymnosperm phyla

cycads, gingkos, conifers

cycadophyta

earliest; spreading, palm-like leaves, pollinated by beetles

gingkophyta

gingko biloba, fan-shaped leaves, dioecious, resistant

coniferophyta

most diverse, cones, gnetales

microstobili

male cones; produce microspores via meiosis; pollen grains

megastrobili

female cones; produce megaspores via meiosis within megasporangia

complete flower

sepals, petals, stamens, carpels

sepals

protect unopened flower bud

petals

attract pollinators

perianth

petals and sepals

stamens

filament and anther

filament

elongated stalk holding the anther

anther

sac containing microsporangia that produces pollen grains

pollen grains

male gametophyte

carpels

stigma, style, ovary, ovules

stigma

sticky surface that receives pollen grains

style

elongated neck that pollen tube grows down

ovary

swollen base enclosing one or more ovules

ovule

megasporangia; female

perfect flower

has both stamens and carpels; bisexual

imperfect flower

lacks stamens or carpels; unisexual

monoecious plant

male and female flowers occur on the same plant

dioecious plant

male and female flowers occur on separate plants

simple fruit

single ovary from one carpel; cherry, pea pod

aggregate fruit

single flower with multiple carpels; raspberry

multiple fruit

derived from inflorescence, cluster of flowers; pineapple

accessory fruit

includes non-ovarian floral tissue

secondary metabolites

organic compounds not directly required for survival, but essential for defense, structure, and attraction

terpenes

rubber, citronella, turpentine, amber

phenolics

cinnamon, vanilla

alkaloids

caffeine, nicotine, morphine, cocaine

domestication

process of artificial selection

loss of shattering

genetic modification where seeds remain attached to central stalk for easy harvesting