Transcript Plants, Fungi and the colonization of Land

Plants, Fungi and the
colonization of Land
HBio Ch 17
What is Kingdom Plantae??
• strictly Multicellular –
specialized tissues and systems,
including growth regions
(meristems), true stems and
leaves
• Chlorophylls a & b, plus
accessory pigments
• Store food as starch, cellulose in
cell walls
• Sexual & Asexual reproduction
Kingdom Protista vs. Kingdom Plantae
Alternation of Generations
Sexual Reproduction -
• Life cycle alternates between
gametophyte generation
(haploid)
–makes gametes
• Sporophyte generation
(diploid)
• makes spores
–embryophytes – multicellular, dependent
embryo at gametophyte stage; differs from
algae
Algae life cycle
alternation of generations
How did life emerge from the sea?
Symbiosis led to invasion of land
- Fungal Partners • Lichens
– Cyanobacteria or algae
+ fungi
– Pioneer species
• Make soil
– Ecological indicator
Kingdom Fungi
Kingdom Fungi
• Mostly multicellular, one
unicellular
• Extracellular
digestion/absorbtion DECOMPOSERS
• Sexual (mating strands) and
asexual reproduction
(fragmentation, budding)
• All mass of a fungus is one cell
type
– Hyphae (singular),
mycelium (mass of hyphae)
• Mushroom is the “sexual
organ”
• Cell wall made of chiton (like
insect exoskeleton)
• More closely related to animals
Pathogenic Fungus (mycosis)
Where did plants come from?
-green & red algae (K. Protista)
charyophyceans
• What is needed to move out of the water
environment of algae
– What “concerns” do plants have that algae
don’t?
Earliest plants
• Bryophytes
– One simple step up
from algae
– Non-vascular
• O&D
– Haploid spores
produced, not seeds
Later - Vascular plants (bigger, better, faster, more)
• Tracheophytes
– Able to survive dryer conditions
– A way to move water and nutrients
• Xylem & phloem
• Roots, stems, leaves
– Symbiosis with fungi
• mycorrhizae
Protection from dessication
• Cuticle
• stomata
And even later, a way to survive
tough times…
• Non-seed plants vs. seed plants
Sexual Reproduction
• Spore
– Haploid tissue
– can’t survive
long without
water
• Seed
– Embyro is diploid
tissue
– Embryo +
endosperm
(triploid tissue) +
seed coat
– Can wait for
conditions to be
right for survival
And more complex ways of making
& distributing those seeds…
• Gymnosperm vs. Angiosperm (monocot/dicot)