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 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?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)