23: seed plants - angiosperms Flashcards
(23 cards)
what are the reproductive structures called in angiosperms?
flowers and fruit
angiosperm groups?
- monocot
- dicot
cotyledon
embryonic leaves
how many cotyledons do the angiosperms have?
- monocot (one)
- dicot (two)
studies suggest majority of dicot species now form a large clade called?
eudicots
a flower contains?
- sepals
- petals
- stamens
- carpels
sepals
enclose the flower
- green and leaf-like
petals
are brightly colored to attract pollinators
stamens
consists of a stalk (filament) and anther where pollen is produced
carpels
produce ovules
carpel is made up of?
- ovary
- style
- stigma
flower ovary
fertilization site, protects ovule
style
elevates the stigma to make it accessible to pollinators
stigma
where pollen is received
difference between complete and incomplete flowers?
complete flowers have all four organs (petals, sepals, carpel, stamens), incomplete flowers are missing one or more
how is a fruit formed?
when the ovary wall thickens and matures, double fertilization
other functions of fruits?
protect seeds and aid in dispersal
life cycle: angiosperm
in a mature flower, the anther releases microspores that turn into pollen grains. the pollen grains go through a pollen tube to reach the egg nucleus inside the ovary to fertilize which forms the zygote - that is now encased in a 3n endosperm, growing into the mature flower on a sporophyte plant
after meiosis, each microsporangium contains?
spore tetrads that produces pollen grains containing the male gametophyte
micropyle
a small pore in the integuments of the ovule
when does double fertilization occur?
when the pollen tube discharges 2 sperm nuclei into the female gametophyte
how does the endosperm develop?
after one sperm fertilizes the egg, others combine with the two nuclei in the central cell
function of endosperm
nourishes and supports the developing embryo, stores food
