evolution of plants Flashcards
what was the first direct evidence of a plant
- cooksonia
- no leaves, roots, or flowers
had vascular tissue to conduct water
liberating spores
advantages of plants living above water line
- brighter sunlight
- more CO2 in air
- abundance of nutrients on shoreline
disadvantages of plants living above water line
- dry environment
- strong affect of gravity
- no nutrients in atmosphere
- rapid changes in temp
what is the apical meristem
region of stem cell division at tip of roots and shoots
what does the cuticle do
protects against desiccation
what are bryophytes
paraphyletic group of non-vasular plants
–> don’t produce seeds or flowers
what is the life cycle of a bryophytes like
-dominated by gametophytes
- no vascular system (stem/rods)
- spore germination and sperm cell swimming depends on water
what are rhizoids
filament that attaches to substrate
what is vascularization
presence of lignified tissues that transport water, nutrients and sugars through plant
what are the 2 transport tissues in plants
xylem (water, minerals to leaves), phloem (sugars)
where are spores produced
leaves
homosporous vs heterosporous
homosporous: 1 type producing bisexual gametophyte
–> most seedless vascular plants
heterosporous: 2 types producing male or female gametophyte
–> all seed plants
what are the advantages of heterospory
specific functions for each sport
seperate female gametophyte can better nourish embryo
–> no energy spent producing male gametes
higher genetic diversity
what are spermatophytes
seed plants
what are the 5 key innovations of seed plants
1) extremely reduced gametophyte is protected from environmental stresses
2) ovule: structure containing megasport
–> fertilization without water
3) heterosporous
–> microspore: male gametophyte, can disperse farther
–> megaspore: female gametophyte, nourishes embryo
4) pollen grain: male gametophyte enclosed in pollen wall
–> can disperse far
5) production of seed
–> increases survival of plants
