lecture 8 Flashcards
what are angiosperms
plants that have reproductive organs in flowers and seeds enclosed in fruits
angiosperms are the sister group of the
gymnosperms
what are the six main synapomorphies of angiosperms
- have flowers 2. xylem has vessel cells along with tracheid 3. they do double ferritization 4. germination of pollen on stigma 5. leaves with network of veins 6. have triploid endosperm (nutritive tissue)
what type of cell in the xylem evolved first
the tracheid’s evolved first and most vascular plants have these cells
what types of vascular plants ONLY have tracheids (no vessel cells)
ferns and gymnosperms
what are flowers
modified stems with flower parts being modified leaves
what do flowers and fruits do for the plants
they increase the reproductive success of angiosperms
what are petals
leaves towards the center: inner leaves in flower
what are a collection of petals called
corolla
what are sepals and petals together called
perianth
what are composites
flowers made up of flowers
what are sepals
occur below or outside of flower: outer leaves in flower
what are the collection of sepal called
calyx
what is an inflorescence
group of flowers
what is a carpel
modified leaf in which ovules and seeds are enclosed in
what is a pistil
one or more fused carpels containing the ovaries
what are stamens
they bear the male microsporangia (pollen)
where can you find the male microsporangia in a flower
in the anther
what is a stigma
sticky part that pollen sticks to
what is the main hypothesis of how carpels evolved
fertile leaves rolled inwards enclosing the megasporangia inside the leaf
what is the microgametophyte of seed plants
pollen/pollen grains that develop in anther
what is pollination
movement of pollen from anther to stigma, requires germination of pollen cell on stigma
how are pollen grains made
microsporangium creates 4 haploid cells under meiosis and each microspore under goes mitosis and forms 2-cell pollen grains (NO CYTOKINESIS OCCURS)
what are the two cells in the pollen grain called
generative cell and tube cell
what is a generative cell
divides by mitosis to form 2 sperm cells
what is a tube cell
forms the pollen tube
what is the symbiotic interaction of pollination
mutualism
most angiosperms are pollinated by what and have what
they are pollinated by animals and they have coevolved
what are some characteristics that seem to be associated with increased number of species
- reduced flower parts 2. differentiation of petals and sepals 3. change from radial to bilateral symmetry
flower produces what for animals
nectar and pollen and specialized colors to attract them
what are perfect flowers
have both megasporangia and microsporangia in same flower (hermaphroditic)
what are imperfect flowers
have two flower type, male and/or female on each plant (unisex)
imperfect flowers can be what two things
monoecious or dioecious
what is the biggest issue for inbreeding of perfect flowers
it decreases heterozygosity by 1/2
what are self-incompatibility plants
plants that reject pollen from same plant
what is an example of flowers trying to stop inbreeding
heterostyly: promotes outcrossing, the styles have different lengths relative to the stamens
when would inbreeding be helpful
if plant is rare or isolated, few or no mates
what is bakers law
plants that are successful colonists are often self compatible
what is a fruit
a mature ovary containing seeds
when do fruits grow
they develop from the ovaries AFTER fertilization
what part of the flower turns to fruit
carpels
what part of the dandelion is a fruit
the aerial seeds
do dandelions cause allergies and if so/not, why?
they do not because the seeds are fruits and they dont contain pollen
what is a berry
simple fruit (fleshy and several seeds)
what part of the strawberry is actually the fruit
the seeds on the outside
