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Chapter 1 Introduction to Plants and Botany
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Topics Why knowledge in Botany is crucial? What is a plant?
Kingdom Plantae Origin of photosynthesis Origin of plants
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Why Botany? Me, others and abiotic environment
Buildup of atmospheric CO2 - many sources - global climate change/warming CO2 removal and O2 release - only one way - Can plants reverse the CO2 accumulation? - plants have changed earth’s climate - impacted evolution and biodiversity Plants & People: Food - agriculture and human society today; Fiber - keep us unnaked; Lumber and paper - forestry and wood-based industries; Chemicals - Phytopharmacognosy, Dyes, Flavors, Perfumes, Pesticides, Preservatives, Texture-makers, Hormones; Biotechnology; Beauty and Spirituality
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Plants – Kingdom Plantae
Defining the term, plant, is difficult Inclusion or exclusion of some groups Green algae - similar biochemistry Archaeplastids – plants+green and red algae phytoplanktons – CaCO3 tests – global CO2-O2 balance Brown algae: Is it a plant?
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Plant Systematics - Natural selection
Organisms make non-identical offspring whose features pass to its offspring Offspring with features that are well-adapted to the environment reproduce more New phenotypes arise periodically by mutations - P=G X E Natural selection - new features are eliminated or continued/balanced Evolution by natural selection is consistent with: observations on nature/life experimentation chemistry and physics
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Origin of photosynthesis and plants
Life on earth ~3.5 bybp with prokaryotes (bacteria and later archaeans) Photosynthesis bybp in cyanobacteria mainly Organelles by endosymbiotic events (1.5 bybp) followed by division of labor and specialization Eukaryotes nuclei and other organelles (plants, fungi, animals, algae) DNA became stationary in its own organelles Those with mitochondria evolved to be protozoans, fungi, and animals Those with mitochondria + chloroplasts evolved into plants and algae – plants evolved from green algae ~475 mybp
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Photosynthetic bacteria
Cyanobacteria – oxygenic - water is e donor - make O2 Purple and purple sulfer bacteria, green sufer and green gliding bacteria etc. - nonoxygenic - H2S is a main e donor Chl a + c/d + carotenoids Archaeplastid super group Chl a + b + carotenoids
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Origin of plants Green algae to Bryophytes (~475 mybp) to Tracheophytes Flowering plants evolved mybp Many characteristics evolved with/following the flower Fruits Simple, flat, broad leaves Complex vascular syst. Wood Most dominant today Cladogram NEXT
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