Lesson 7- Plants 1 Flashcards
Plants evolved from…
Charophyta, they share the characteristic of sporopollenin
Challenges of evolving out of water
Lack of water, UV radiation, gravity
Alternation of Generations (plant derived traits)
Both a multicellular diploid and multicellular haploid phase
Multicellular dependent embryo (plant derived traits)
Drains nutrients from female gametophyte
Sporangia (plant derived traits)
Chambers that undergo meiosis to produce haploid spores
Gametangia (plant derived traits)
Produces gametes, Antheridia makes sperm and Archegonia makes eggs
Apical Meristems (plant derived traits)
Undifferentiated “Stem Cells” often found in shoots or roots
Non-Vascular Plants (475 mya)
Like damp places, short because they can’t transport water upwards, use osmosis, Gametophyte-dominant (n), have rhizoids to anchor themselves in place of roots, no leaves
Phylum Bryophyta (non-vascular) and Life Cycle
Mosses.
A (n) gametophyte produces a (2n) sporophyte stalk, which has a sporangium (2n) that undergoes meiosis to make (n) spores. The (n) male gametophyte has an (n) antheridium that makes sperm which flows through water to the egg within the (n) archegonia within the (n) female gametophyte. After fertilization, a (2n) zygote grows out of the female gametophyte and becomes a (2n) sporophyte.
Phylum Hepatophyta (non-vascular)
Liverworts
Phylum Anthocerophyta (non-vascular)
Hornwarts, have horn-like sporophytes that are photosynthetic (therefore more independent of the gametophyte)
Vascular Seedless Plants (425 mya)
Sporophyte-dominant. Have vascular tissue, true leaves, and true roots (which both anchor and absorb nutrients).
Microphylls
Small leaves- more water, less sun
Megaphylls
Big leaves- less water, more sun
Phylum Lycophyta (vascular seedless)
Heterosporus, very few species
Phylum Monilophyta (vascular seedless)
Homosporus, ferns
Homosporus Fern Life Cycle
A (2n) sporophyte has a (2n) sorus on its leaves that contains a (2n) sporangia that undergoes meiosis to produce (n) spores which become a (n) bisexual gametophyte that contains both archegonium (w/egg) and antheridium (w/sperm). After fertilization (sperm swim in water), the (2n) zygote grows out of the gametophyte to become a (2n) sporophyte.
