Plant Diversity lecture covering Mosses, Ferns, Gymnosperms and Angiosperms, based on Chapters 29 and 30 from Campbell & Reece "Biology" 8th edition (International). For ACS Biology 10, Sofia Bulgaria. March 2010
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Plant Diversity Jewett
1. Plant Diversity (Chapters 29 & 20) All you ever wanted to know about plants…but were afraid to ask. Jeff Jewett American College of Sofia March 2010 Version 1.0
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8. Moss Life Cycle Animation http://www.sumanasinc.com/webcontent/animations/content/moss.html
25. Yes No No No Flower / Fruit Pollen Pollen Sperm (needs H2O) Sperm (needs H2O) Male Gamete (1N) Seed Seed Spore Spore Seeds / Spores (2N) Yes Yes Yes No Woody Stem (with lignin) Yes Yes Yes No Vascular Tissue Sporophyte Sporophyte Sporophyte Gametophyte Dominant Life Form Angiosperms Gymnosperms Ferns Mosses
Editor's Notes
Vascular tissue – cells joined into tubes to transport water & nutrients throughout a plant Seeds – an embryo and a food supply, surrounded by a protective coat (CR p 618)
Short because they are non-woody and can’t support themselves, also no vascular tissue to transport water/nutrients Moist environment because the sperm have to swim to egg Sexual reproduction requirements keep mosses close to each other (sperm has to swim) Gametophytes are dominant part of life cycle (the one you think of as “mossy”)
Elevation of stalk (seta) helps spore dispersal Sporophytes have stomata to regulate water loss (also found in all vascular plants)
You’d have to dig around on the ground on your hands & knees to see fern gametophytes, which are the dominant form in mosses Lignified stems allow plants to get taller – arms race for sunlight! Non-woody plants rarely get more than 20cm tall. Lignin also allows real roots – get water, nutrients, and anchor (needed if you’re getting TALL)
Fern Frond Sori (sing: sorus) where the spores come from Ferns took carbon out of atm 350MYA, cooled atm, turned to coal, burned, CO2 in atm, warming in atm
Seed plants about 360 MYA Seed = detachable, mobile womb! (embryo plus support structure)
Microscopic gametophytes allow eggs to stay inside, protected from drying out and UV stress Heterospory (male and female spores) – megaspore are female (big pine cones), microspores are male (tiny cones)
Wind-pollinated flowers usually lack petals (grasses) Stamen – produce pollen Carpel – female parts…stigma catches pollen, style delivers, ovary receives