Lecture 3 -- Plants Flashcards
div. anthophyta – flowering plants
most successful group , flowers +fruits, seed plants
Conifer review:
seed+pollen, slow reproduction, gymnosperms, “naked seeds” (don’t have covering)
plant evolution
- land plants 2. vascular tissue 3. seed, pollen 4. flower
anthophyta appeared when, and what was this called
appeared around 150 MYA and was called the angiosperm terrestrial revolution
angiosperm terrestrial revolution
angiosperm species exploded, diversification of angiosperm’s occurred at the same time as diversification of other organisms
facts about percentage of plants animal and fungi
85% of plant, animal, and fungal species live on land, half of these species live in tropical rainforests.
angiosperm diversity +species number
insect pollution – does not occur in gymnosperms.
flexibility in seed production and dispersal.
greater genetic and phenotypic flexibility in cell and shoot elongation.
more complex mechanisms for activating and repressing the genes.
greater complexity of the flower.
div anthophyta facts/ characteristics
300,000 named, 400,000 estimated
reproductive organs in flowers,
sporophyte dominant (the thing you see)
heterosporous
microgametophyte = pollen
megagametophyte: 8 nuclei, 7 cells
triploid (3n)
endosperm feeds embryo
4 whorls meaning
a set of structures coming out of the same plant
flower structure
big U: sepal (x2 calyx), little u: petal (x2 corolla) v with two balls on either: filaments, ball = anthers (sporangium), weird shape with six circles: top = stigma, middle = style, bottom = ovary, circles = ovule
Stigma + style + ovary =
carpel (gynoecium) “house of women” also known as pistil carpel
Anther + filament =
stamen (adroecium) “house of men”
stigma
where pollen lands
when anthophyta occurred, what did it split into
150 MYA occurred, 125 MYA split into eudicopts and monocots
example of monocot
grasses, corn, wheat, rice,
example of eudicots
oaks, maples, dandelions
Mono
1 little seed leaf
eudi
2 seed leaves
characteristics of monocots and eudicots
MONO:
1 cotyledon
parallel veins
vascular tissue scattered
no main root (fibrous)
pollen grain with one opening
floral organs in multiples of 3
EUDI:
2 cotyledons
netlike veins
vascular tissue in ring
main root (taproot)
pollen grain with 3 openings
flower organs in multiples of 5
male and female sex organs within ONE flower
hermaphroditic
male parts and female parts are far away from each other to prevent self-pollination
how man angiosperm species are hermaphroditic
85%
monoecy
“one house” but separate male and female flowers. However, on the same individual (paper birch)
dioecy
“two houses” male and female sex organs on different individuals (willow)
pollination
arrival of pollen on stigma (flowering plants), or receptive female cone (conifers)
where does pollination occur
occurs only in seed plants (angiosperms and conifers)
how do conifers pollinate
wind
how do flowering plants pollinate
insects, birds, bats, wind.
pollination in angiosperms; what is the reward for pollinator
nectar and pollen (nectar is sugar water)
nectar: birds and bees.
pollen: bees
what does advertisement by plant mean
showy flower, odor
what are both reward and advertisement to a plant
costly
pollination syndromes
varying characteristics of flower, door, etc. so pollinator visits.– type of convergent evolution
pollination by bees
syndromes:
shape – various – highly specialized, or not
color – various – including yellow, blue, orange, NOT RED because they cannot see it
odor – none, or highly specialized
pollination by bats
syndromes:
shape – tubular, open at night
color – yellow or white
odour – strong and sweet
nectar – large quantity
pollination by birds
syndromes:
shape – tubular
colour – red most common, also yellow
odour – none
nectar – large quantity, often weak (20% sugar)
pollinated by wind
syndromes:
shape – not showy (reduced petals)
odor – none
nectar – none
pollen – in large quantity.
fact about pollinators and plants
– pollinated by many animals species
– pollinated by ONE animal species
– provide no reward : deceit pollination
deceit pollination example
pink lady’s slipper orchid – makes showy flower but provides no nectar.
pollen is held in 2 packets, packets are closed so pollinator cannot use them however, the pollen does in fact get stuck to pollinator.
this is achieved by having the bee check the flower out, but as it exits, it brushes by the male and female parts, collecting or distributing pollen, which is the only way to get out.
pollination syndromes are not perfect
pollination of Cardinal flower by moth. Moth obtains the nectar but does not carry pollen due to its very long tongue allowing it to obtain reward and not do any job.
life cycle of angiosperm
seed (containing embryo 2n, seed coat 2n, endosperm 3n) – anther – male part: microsporangium (microsporocyte) – meiosis – 4 pollen grain (2 functional sperm cells) – pollen opens up and extends down the stem to find ovule – Female part: – from anther ovary (in ovule) – megasporangium – megaspore (divides 3 times) – central cell 2n, and egg n, sperm and egg fertilize – (double fertilization because 2 sperm, 1 for egg, 1 for central cell) – zygote 2n, endosperm 3n – seed
double fertilization
critical feature, 2 functional nuclei, 2 sperm nuclei in pollen, 1 fertilizes egg (embryo, 2n, diploid), and 1 fertilizes central cell (endosperm, 3n, triploid)
Angiosperm ovules + ovaries
ovules become seeds, ovary become fruit
fruit examples with more than one seed
watermelon, banana, grape, pea pod, apple
fruit examples with only one seed
cherry, peach, acorn, wheat, coconut, grain, rice.
dispersal of seeds and fruits 3 types
wind: maple, cotton wood
water: coconut, water lily
animals: blueberry, cockleburr
nourishing embryo angio vs conifer
conifer: megagametophyte (n)
angiosperm: endosperm (3n)
what is the endosperm a principal of
principal food stuff of civilization, more than 1/2 of direct daily calories
conifers vs flowering plants, differences
Reproductive structure: conifers = cones flowering = flowers
microgametophyte: conifers = pollen, flowering = pollen
pollen dispersal: conifers = wind, flowering = wind, animals, water
megagametophye: conifers = many cells, flowering = 7 cells
nourishing embryo: conifers = megagametophyte, flowering = endosperm.
seed: conifer = naked, flowering = covered.
Land plants structure + growth
two systems in vascular plants: roots and shoots, they differ anatomically.
nodes
where leaves emerge from
internodes
regions between nodes
blade
each leaf has a bead
petiole
part of leaf attached to stem/shoot itself
axillary bud
known as the armpit, area between petiole and stem, can grow into a new shoot
vegetative shoot
it can make more leaves and more shoots
evolutionary adaptations of stems
rhizome - vertical shoots
stolon - grow along surface
tuber - stolon or rhizome
evolutionary adaptations of roots
prop roots, storage roots, green roots, pneumatophores, strangling aerial roots.
plant cell walls characteristics
mostly cellulose, (polysaccharide of glucose units), cellulose lined up forms microfibril, which are adjacent and parallel to cellulose molecules, it is extracellular, there are two kinds primary and secondary.
primary cell wall charactewristic
thin and in all cells
secondary cell wall characteristic
thicker, in some cells,
functions of plant cell wall
- determines + maintains shape
- provides support and strength
- controls rate and direction of cell growth and regulates cell volume
- responsible for plants’ architectural design
- physical barrier to pathogens and water in suberized (waxy) cells
- wall is porous and allows free passage of small molecules
- carbohydrate storage.
plat cell wall composition
cellulose – around 36 chains bond to make microfibril
– cross linking glycans (bond with cellulose) – hemicellulose
– pectin (jellylike; glue)
-
draw cells sticking together and label `
should be for, with plasmodesmata, middle lamella, and say that it is stuck by pectin.
3 tissue systems in vascular plants
dermal tissue, vascular, and ground
dermal tissue characteristics
single layer, secretes cuticle
vascular tissue characteristics
xylem and phloem, support and supply
ground tissue characteristics
bulk of young plant, fills space between dermal and vascular, storage, photosynthesis, support
plant cell types
dermal : epidermis
ground: parenchyma, collenchyma, sclerenchyma
vascular : tracheids and vessel, sleeve elements
epidermal cells
outermost cells, single layer coveringg leaves, shoots, stems, of non woody plants.
epidermal cell functions
waterproofing, protection from pathogens,
cuticle
formed by the epidermal cells, outermost part is wax, cuticle protects against water loss, pathogens, UV radiation
