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)