Theme 2 Classification Of Land Plants Flashcards
What are the defining characteristic of land plants
Eukaryotes
Almost all photoautotroph
Multicellular
Sessile
Cell walls
Alternation of generation
Embryo (sporophyte) kept in gametophyte tissue
What does heterotrophic mean
Having no chlorophyll (not photosynthetic)
How do heterotroph plants get atp
They get a organic carbon source from other plants
What significant features do plant cells have
Primary cell wall which surrounds plasma membrane and organelles
Plant walls Have cellulose (pure glucose) fibres mixed in with hemicellulose
Cella are rigid but flexible (can expand)
Some plant cells have ___ cell wall
Do all have this?
Secondary
No all have primary some have secondary
What type of cells have secondary cell walls
Xylem and sclerenchyma cells
What is diff about the secondary cell wall
The cellulose fibres are now anchored with lignin.
Lignin make it stronger and more rigid and makes waterproof barrier
What provides the rigidity of a cell
The turgor pressure of the vacuole pushing against the cell wall
What is hypertonic what is the effect
Less water on outside of cell than inside so water shift outside to balance.
Cell becomes plazmolyzed (no moisture all water leaked out)
What is isotonic what is the effect
Same amount water on outside than inside of cell, equilibrium.
Means cell is flaccid (plants droop and need to be watered)
What is hypotonic what is the effect
More water on outside of cell than in
So water shift inside cell to balance
Cell become turgid and rigid due to turgor pressure
What does alternation of generation mean for plants
Plants alternate from haploid (gametophyte) to diploid (sporophyte) generation in their single life cycle
What is the gametophyte
The multicellular stage of the haploid generation of plants
What happens to the embryo (seed) during fertilization
It retained on the female gametophyte because it can’t survive yet
It germinates on the mother
What is the ploidy of a
sporophyte
Gametophyte
Spores
Gametes
Zygotes
Offsprings
2n
n
n
n
2n
2n
What is the life cycle of a plant
The sporophyte creates spores through meiosis which then turn into the gametophyte through meiosis
Then gametes are formed and through fertilization become the zygotes then offspring
Is the sporophyte multicellular or unicellular
Spores?
Multicellular
Unicellular
How are land plants classified
Based on presence of
vasculature
seeds
What are vascular bundles
The circulatory system or network that addresses the plants water and nutrient needs
How much water is used by plants
What happens to the rest
10% used up
90% evaporated by vasculature
What four cells make up the vascular bundles
Xylem
Phloem
Parenchyma (undifferentiated cell)
Fibre cells (schlerenchyma)
What do schelerenchyma (fibre cells) do
Provide ridged support to xylem and phloem
They provide thc
What does xylem do
Water conducting cells
What do phloem cells do
Transport sugars and other solutes
What is the greatest advantage of vasculature
Makes cells rigid, help them grow taller and taller
More growth means more sunlight Allows for more photosynthesis
What nonvascular plant is closest to lycophytes
Hornworts
What is the order of evolution of plants
First nonvascular (mosses)
Then seedless vascular ( ferns)
Then vascular seeds (gymnosperms angiosperms)
Or
Bryophytes
Pterophytes
Gymnosperms
Angiosperms
What are characteristics of non vascular plants
Lack vasculature
Haploid generation is dominant
Bryophytes
What are characteristics of vascular seedless plants
Have vasculature no seed
Diploid (sporophyte) Gen dom
Lycophytes (selaginella)
Pterophytes (fern)
What are characteristics of vascular seed plants
Have vasculature and make seeds
Diploid (sporophyte) Gen dom
Gymnosperms and angiosperms
Why is staying in diploid more favourable
More chance of survival and getting favourable mutations to evolve
What are characteristics of non vascular plants (bryophytes)
First on land
No conducting tissues (vasculature)
Small grow close to ground on wet sites
Poikilohydric
What does poikilohydric mean
Have little control over internal water content
Can’t restrict water loss
If habitat dries out, organism dries out
Drought tolerators
How to poiklohydric things stay alive in droughts of all drought tolerators
Osmotic adjustments and cell wall elasticity
What is a drought avoider
Highly evolved plants that change leaf orientation leaf area and stomata conductance
To avoid drought
Are gymnosperms poikilohydric
No
What is the life cycle of a moss (bryophyte)
In the gametophyte stage, rhizoids (root like structures) keep them upright
The diploid sporophyte realeases spores and then the spores become protonema with rhizoids (this is the amplification step)
The protonema buds turn into male gametophyte with antheridium or femal with archegonium
The antheridium shoots flagellated sperm (need water) to archegonium which has spent attractant
Zygote it formed and is retained in archegonia and it turns into sporophyte
What is the sporangium in mosses
On top of the sporophyte it releases spores
Contains gametangia
It’s haploid and unicellular
What is the biggest disadvantage for bryophytes
Need water for reproduction because of flagellated sperm
When do bryophyte spores germinate
Only under favourable conditions,
Wait for water
Why are mosses important
They cause less loss of nitrogen in the ecosystem
What are microphylls
They are little narrow leaves that branch off the main stem and have one strand of vasculature
The represent modification of stems they’re only present in lycophytes
What are megaphylls
The evolved version of microphylls
Broader leaves with multiple veins, present in all other vascular plants
Not present in lycophytes
What characteristics to pterophyta (ferns) have
Most abundant seedless vasculature plants, have mega phyll
Large
Spores develop on underside of the fern leaves then into gametophytes (no protonema)
Antheridia and archegonia develop on underside of the gametophytes.
Have roots not rhizoids
Can survive without moisture
What are antheridia and archegonia
Sperm cells
Egg cells
Life cycle of a fern (Pterophyte)
Sporangia on underside of leave are released
Spore germinates into gametophyte
Free living gametophyte has both antheridium and archegonium (hermaphrodite)
The antheridium burst when water and the sperm swim toward archegonium
Fertilization makes zygote
The sporophyte grows on the
gametophyte
What is the prothallus in ferns
Where is the archegonia and antheridium
Heart shaped gametophyte
Anterior side where notch is (archegonia)
Posterior (antheridia)
What is antheridiogen and what does it do
Shuts down the notch that has archegonia on other fern gametophytes
Does this to get sperm from them and block from giving it to themselves
Increases genetic diversity and less competition for sperm
What type of seeds do gymnosperms and Angiosperms have
Naked
Covered
What are some characteristics about gymnosperms
Sporophyte phase dominant
Seeds unprotected
Makes reproductive structure that contain haploid spores
Pollen grain make non motile sperm
No water needed for pollen transfer
Bryophytes are what type of hydric
Poikilohydric
