Plant Diversity Flashcards
Chapter 29
what is the closest relative of land plants?
green algae called “charophytes”
what four characteristics do land pants share with ONLY charophytes
1) rings of cellulose-synthesizing complexes
2) peroxisome enzymes
3) flagellated sperm with similar structure
4) formation of phragmoplast
what’s a phragmoplast?
microtubules formed along the midpoint during division
why are charophytes considered the closest living relative between plant and algae?
similarities between nuclear and chloroplast genes
what is sporopellenin?
layer of polymer that prevents zygotes form drying out in charophytes and is also found in plant spore walls
what happened when charophytes moved onto land
- unfiltered sun
- more plentiful CO2
- nutrient-rich soil
- few herbivores and pathogens
what challenged did land present?
lack of structural support, scarcity of water
what five traits appear in nearly all land plants but are absent in the charophytes
1) alternation of generations and multicell embryos
2) walled spores produced in sporangia
3) multicellular gametangia
4) multicellular embryo
5) apical meristems
what is alternation of generations?
plants alternate between two multicell stages, the reproductive cycle is alt of gen.’s
what is a gametophyte?
haploid; produces two haploid GAMETES via MITOSIS
what is a sporophyte?
fusion of gametes produces a diploid sporophyte which produces haploid SPORES via MEIOSIS
what are placental transfer cells?
they transfer the nutrients from parent to embryo
what are land plants called embryophytes?
the dependency of the embryo on the parent
where do sporophytes produce spores?
sporangia
what are sporocytes?
diploid cells that undergo meiosis to generate haploid spores
what organs are used to produce gametes in plants?
gametangia
male gametangia? female gametangia?
male: antheridia
female: archegonia
what are apical meristems?
plants sustain continual growth there and the apical meristems differentiate into various tissues
what’s a cuticle?
a waxy covering of the epidermis
what’s mycorrhizae
symbiotic associations between fungi and land plants that may have helped plants without true roots to obtain nutrients
fossil evidence says plants were on land how long ago?
475 million years ago
non-vasc plants
bryophytes
- liverworts
- mosses
- hornworts
seedless vasc plants
- lycophytes (club mosses)
- monilophytes (ferns)
seed vasc plants
- gymnosperms
- angiosperms
how can land plants be informally grouped?
presence of vascular tissue
what are non-vasc plants commonly called?
bryophytes
bryophytes are what type of group?
not a monophyletic
seedless vascular plants can be divided into what two clades?
lycophyta, monilophyta
lycophyta
club mosses and relative
monilophyta
ferns and their relatives
gymnosperms
“naked seed” plants including conifers
angiosperms
the flowering plants
bryophytes three phyla
liverworts, hornworts, mosses
bryophyte vs. bryophyta
- byrophyte: non-vasc plants
- bryophyta: phylum of mosses
which ____phytes are longer-living and larger?
gametophytes are larger and longer-living than sporophytes
rhizoids
anchor gametophytes to substrate
height of gametophytes constrained by…
lack of vascular tissue
what does a sporophyte consist of?
foot, seta (stalk), capsule (sporangium), peristome (capsule discharges spores via this)
moss environments?
capable of inhabiting extreme environments but are common in moist forests and wetlands
benefits of moss?
some help retain nitrogen in soil, used to insulate structures, used as footwear
peat
used as source of fuel; extensive decayed amterial
sphagnum
important global resovoir of organic carbon
what were the prevalent vegetation during the first 100-million years of plant evolution?
bryophytes and bryophyte-like
when did vasc plants begin to diversify?
devonian and carboniferous
how can plants grow tall?
vasc tissue
seedless vasc plants restricted to what environments
moist environments; flagellated sperm
how are living vasc plants characterized?
- life cycles with dom. sporophytes
- vasc tissue (xylem and phloem)
- well-developed roots and leaves
xylem
conducts water and minerals and includes tracheids
trachieds
dead cells in xylem
lignin
strengthen water-conducting cells
phloem
living cells and distributes sugars, amino acids, and other organic products
two types of leaves
- microphylls: single vein
- megaphylls: highly branched vasc system
evolution of microphylls
outgrowth of stems
evolution of megaphylls
evolved webbing between flatted branches
club mosses and spike mosses not “true mosses?”
have vasc tissue
most diverse seedless vasc plants
ferns (120,000+), diverse in tropics also thrive in forests
horsetails
diverse during carboniferous now restricted to genus equisetum
whisk ferns
resemble ancestral vasc plants but are closely related to modern ferns
decaying plants of carboniferous forests…
coal
