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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 GenerationsSexual 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 cyclealternation 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
than to plants in physiology
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)