Chapter 17- Plants, Fungus and the Colonization of Land Mycorrhiza- fungus root – Roots of plants covered with fungus growth- increases absorption of water from soil Plants- multicellular photosynthetic eukaryotes Plant Evolution – Non-vascular plants- Bryophytes – no vascular tissue, simplest Ex: algae, moss – Vascular Plants or Seed Plants- evolved transport system with specialized vascular tissue for land life Vascular tissues: xylem- brings water and minerals up; phloem- distributes sugars up and down as needed Cuticle and stomata evolved for land life Most have roots, stems and leaves Reproduction – Make sperm and egg (gametes) in gametangia= protective covering of cells for land based reproduction – Embryophytes- multicellular, embryo nourished by parent- separates plants from algae Spores or seeds- adapted for land survival

2 types of seed plants: Gymnosperms and Angiosperms – Gymnosperms- do not form flowers Seeds develop on surface “naked”- not in a fruit Cone-bearing plants – make ovules and pollen grains Ex: pine, fir, spruce – Angiosperms- forms flowers- make pollen and eggs Seeds develop in a protective chamber Very diverse ( species) Flower structure – Specially adapted for process of sexual reproduction – Most contain both male and female reproductive organs – Stamen-male part Anther- makes pollen grains (male gamete) Filament- holds anther in proper position – Pistil- female part Stigma- sticky area that can receive pollen Style- holds stigma in proper position Ovary- makes eggs, can develop into fruit – Accessory organs- petals and sepals – Reproduction involves: meiosis and fertilization

Pollination – Actual transfer of pollen from anther to stigma – Self-pollination- in same plant – Cross-pollination- between 2 different plants – Pollen vectors- (agents of pollination)- wind, water, insects, animals Germination of pollen – After pollination the pollen grain germinates (sprouts) – Growth of pollen grain and formation of pollen tube – Pollen tube allows sperm to travel to egg Fertilization – Pollen tube reaches ovule and releases sperm nuclei Fruits and seeds – Ovary develops into fruit – Each ovule develops into seed – Parts of seeds: Embyro- developed zygote, grows into seedling Seed coat- protects embryo Cotyledon and/or endosperm- stored food for embryo – Monocot- 1 cotyledon – Dicot- 2 cotyledon

Seed dispersal – Eaten by animals and pass through system – Wind, water, hooks/barbs, pressure, fire Seed dormancy- dormant stage until environment conditions are right, then seed grows and develops Seed germination conditions- proper temperature, amount of oxygen, water level Mosses and ferns- alternation of generations mil years ago- seedless plants formed vast coal beds of today = fossil fuels Expanding human pop threatens diversity – People pushing into forests- recently destruction is increasing faster – Many medicines are produced from plants – Goal: encourage sustainable forest management Fungi – Plants moved to land w/ mycorrhizal fungi – Fungi- heterotrophic eukaryotes that digest food externally and absorb nutrients – Reproduce by spores – Lichen- association of algae and fungus, fungus gets home in exchange for housing, water, minerals – Parasitic fungus accounts for agricultural losses – Many are helpful- mushrooms, antibiotics, truffles