Plant Diversity I Flashcards
Plants are ____.
terrestrial organisms that evolved from semi-aquatic green algae.
Shared Characters(Plants)
- Multicellular
- Eukaryotic
- Photosynthetic
- Cell walls contain cellulose
What is the closest land plant relative?
Charophyceans
Charophyceans
Aquatic but living in ephemeral(sometimes water sometimes draught) bodies of water.
- Seasonal waters come in and out force them to adapt to draughts and eventually create land plants
Shared Characters between Plants and Charophyceans
- Rose shaped complexes for cellulose synthesis.
- algae tend to be linear
- Similar peroxisome enzymes
- for toxic and metabolic processes
- Similar flagellated sperm
- Phragmoplast(specialized microtubules) forms during cell division
Shared Characters between Plants and Charophyceans:
cellulose synthesis
Rose shaped complexes for cellulose synthesis.
- algae tend to be linear
Shared Characters between Plants and Charophyceans:
peroxisome enzymes
Similar peroxisome enzymes
- for toxic and metabolic processes
Shared Characters between Plants and Charophyceans:
flagellated sperm
Similar flagellated sperm
Shared Characters between Plants and Charophyceans:
Phragmoplast
Phragmoplast(specialized microtubules) forms during cell division
History of Plant Evolution
- Ordovician Period(480 MYA)
- land invasion
- Only an inch or two tall.
- No vascular structure
- Just a green film by water
- Terrestrial adaptations
- Cuticle – epidermal polymers that act as waterproofing
- helps trap in water to survive draughts
- Sporopollenin – durable polymer that prevents spores / pollen from drying out
- coats gametes to keep them from dying from damage
- Cuticle – epidermal polymers that act as waterproofing
History of Plant Evolution:
Terrestrial Adaptations
Cuticle – epidermal polymers that act as waterproofing
- helps trap in water to survive draughts
Sporopollenin – durable polymer that prevents spores / pollen from
drying out
- coats gametes to keep them from dying from damage
History of Plant Evolution:
Terrestrial Adaptations:
Cuticle
epidermal polymers that act as waterproofing
- helps trap in water to survive draughts
History of Plant Evolution:
Terrestrial Adaptations:
Sporopollenin
durable polymer that prevents spores / pollen from
drying out
- coats gametes to keep them from dying from damage
Not all plants have ____.
roots.
Mycorrhizae(fungus) symbiosis with plant roots
This association is critical to the success of plants roots system as the fungi provides critical water to the roots.
- Fungi facilitated the invasion of land plants
Timeline of Plant development
Non vascular plants – Ordovician period
Vascular Tissue – Silurian Period
Seeds – Carboniferous Period
Unique Plant Characters
- Apical Meristems
- Alternation of generations
- Walled spores in sporangia
- Multicellular Gametangia
- Multicellular Dependent Embryos
Unique Plant Characters:
Apical Meristems
- Group of undifferentiated cells allowing growth
- On roots, stems, and bud tips
- Cells can turn into any other type of cell needed
- Stem cells for plants
Unique Plant Characters:
Alternation of generations
- 2n generation to 1n generation then 2n
- Sporophyte – diploid multicellular organism
- Gametophyte – gametophyte
- They look different
Unique Plant Characters:
Walled spores in sporangia
- Structure that contains spores
- The vessel that contains the spores
- Outside coat
Unique Plant Characters:
Multicellular Gametangia
- Gamete producing organ
- Check slides
Unique Plant Characters:
Multicellular Dependent Embryos
- Mom nourishes offspring just like humans
- Zygote retained within female and embryo nourished
- Offspring grows out of mom but requires nutrients along the way
Unique Plant Characters:
Alternation of generations:
Sporophyte
diploid multicellular organism
Unique Plant Characters:
Alternation of generations:
Gametophyte
Gametophyte – haploid
Evolution of non-vascular seedless plants(Bryophytes)
Ordivician Period.
475 MYA
- Gametophyte is dominant life stage
- Possesses antheridia(sperm) and archegonia(ova)
- Sporophyte grows from archegonium
- Reproduction water dependent
- Bryophyte taxa
Evolution of non-vascular seedless plants(Bryophytes):
Dominant stage of life
Gametophyte is dominant life stage
haploid
- when water hits(rain) = release of spores
Evolution of non-vascular seedless plants(Bryophytes):
Possesses antheridia and archegonia
antheridia(male gametangia)
archegonia(female gametangia)
Evolution of non-vascular seedless plants(Bryophytes):
Sporophyte grows from archegonium
literally grows out of the archegonium(female gametangia)
Evolution of non-vascular seedless plants(Bryophytes):
Reproduction water dependent
Reproduction water dependant (due to flagellated sperm)
- in very wet/damp environments
Evolution of non-vascular seedless plants(Bryophytes):
Bryophyte taxa
- Liverworts
- Hornworts
- Mosses
Evolution of vascular plants(seedless and seed)
Silurian Period(seedless) and Carboniferous Period(seed)
420 MYA
- Vascular Tissue
- Sporophyte dominant
- Roots
- Leaves
- Sporophylls
- Vascular seedless plants
Evolution of vascular plants(seedless and seed):
Vascular Tissue
Cells form tubed to transport H2O and nutrients
- Xylem - water / mineral transport
- Usually roots to rest of plant
- Phloem - sugar / organics transport
- Usually from photosynthesizing organs to rest of plant
- Allows plants to grow significantly larger(up) = major change
Evolution of vascular plants(seedless and seed):
Sporophyte dominant
Bryophite(nonvascular) the gametophyte is the dominant phase
Now the sporophyte is the dominate stage
Evolution of vascular plants(seedless and seed):
Roots
move away from water to avoid competition with other plants
- Anchor plants
- absorb nutrients
- provides support
Evolution of vascular plants(seedless and seed):
Leaves
they evolve leaves and leave it at that
- increase surface area for photosynthesis
Microphyll - spine shaped leaf w/ single strand of vascular tissue
Megaphyll - broad leaf w/ vascular network
Evolution of vascular plants(seedless and seed):
Sporophylls
modified leaves that bear sporangia(has structures on bottom)
- Homosporus - single spore gives rise to both male and female plants (most seedless plants)
- Heterosporus - megaspore becomes female, microspore becomes male (all seed plants)
Evolution of vascular plants(seedless and seed):
Vascular seedless plants
- Lycotphytes
- Horsetails
- Whiptails
Significance of vascular plants (seed and seedless)
- Transformed land / atmosphere
- Facilitated industrial revolution
- everything that died got turned into coal from Carboniferous Period
Extant seed plants origin time
Carboniferous Period
305 MYA
