seed plants Flashcards
types of seed plants
angiosperms and gymnosperms
when do secondary xylem and phloem develop
before progymnosperms
when do seeds develop
before gymnosperms
when does multicellular embryo sac develop
before angiosperm, consists of female gametophyte composed of many cells, causes food source to change
food source for embryo
endosperm
pro gymnosperms
seedless plants with woody growth, leaves are fronds with spores underneath
seed plants gametophyte
dependent on sporophyte (main body), different from independent gametophyte in seedless plants
are spores released into the environment
no, they stay within the flower structure and grow into gametophytes
male gametophyte
pollen
microspore and megaspore main characteristic
heterosprorous
where are megaspores found
ovule
pollen advantage
allows for reproduction without free water
seed function
provide protection and a food reserve for embryonic sporophyte
integument
outside of ovule, develops into seed coat
megasporangium
area inside ovule
micropyle
entry into ovule where sperm germinate into
are sperm usually flagellated in gymnosperm
no, they just move through the pollen tube to produce the embryo, some gymnosperms are flagellated though
where is the gymnosperm seed
on the surface
four gymnosperm groups:
cyads, gingko, gnetophytes, conifers
gymnosperm importance
make up most of the earth’s biomass
cycads -
most primitive seed plants, dioecious, look like shrubs
how were cycads pollenated
by insects, they don’t produce long pollen tubes, have long flagellated sperm, have symbiotic relationships with cyanobacteria
gingko -
living fossil, have dichotomously branched veins, don’t produce woody cones, dioecious, produce flagellated sperm, have large odorous seeds
pollination drops -
feature of wind pollinated plants, landing site to capture pollen, these drops can contain sugars and amino acids as their main components,
angiosperms pollination drop include a wet stigma on the outside of a closed carpel, allows for a sweeter carbohydrate
conifer definition
cone bearing, produce soft wood due to tracheid xylem (not reinforced with lignin), , monoecious, sperm are nonmotile, usually found in dry areas
deciduous (drop their needles)
conifer characteristics
reinforced with sclerenchyma, stay on for years, thick cuticle and hypodermis, sunken stoma
types of megaphylls in conifers
spruces, pines, firs, scale leaves
conifer life cycle:
dominant sporophytes, heterosporous, monecious, meiosis produces microspores and megaspores, resulting in pollen and ovule
seeds can be winged and disperse through air, or dispersed by animals
types of cones
woody, fleshy-coated, fleshy
how do pollen grains disperse
contain air sacs that help with wind dispersal
how many archegonia produced by conifers
two
pine ovule tissue
outside is diploid, inside is haploid
gnetophytes -
only 70 living species,
have xylem made of tracheids and vessels,
cone clusters resemble inflorsecences,
pollen grains produce long tubes to deliver non motile sperms,
carry out double fertilization (one egg is fertilized to produce zygote, other egg fuses with the two polar nuclei to form endosperm)
angiosperms
at least 260000 families
basal angiosperms
different from monocots and dicots, evolved earlier, most don’t have xylem, have radial symmetry, superior ovaries, not many species
amborella
basal angiosperm, monotypic and endemic to New Caledonia , diecious
nymphaeles
basal angiosperm aquatic freshwater plants
austobaileyales -
type of basal angiosperm, star anise is most well known species
chloranthales -
found in tropical areas, early diverging lineage to angiosperms but don’t fit with basal angiosperms, lack vessel elements, aromatic, unisexual and small flowers, drupe fruit
magnoliids -
unfused flowers, numerous leaf shaped stamen, indehiscent fleshy fruit,
ceratophyllales -
only about 10 species, free floating submerged aquatic plants, lack true roots
flower evolution -
decrease in floral parts, inferior ovary, radial to bilateral symmetry
monocots vs dicots -
one vs three pollen grains. female gametophytes don’t produce archegonia, they produce many types of cells, sperm are nonmotile
resin function
ducts to prevent drying
