Download Chapter 29: Plant`s Colonization Green Earth • First 3 bil. yrs, no

Chapter 29: Plant’s Colonization
Green Earth
 First 3 bil. yrs, no land life
 370 mya – forests
 1.2 bya – cyanobacteria
 Tody: ~290k living plants
 500 mya – small plants, fungi, animals show up
Kingdom Plantae
 Multicellular eukaryote
 Cell wall made of cellulose
 Autotrophic (chloroplasts)
o Primary Producers
 Mutualists w/ bacteria, animals, fungi
 Central Vacuole
o Hydrolysis
o Store proteins & ions
o Waste dump
o Poisons for defense
o Pigment proteins attract pollinators
Protist Origin
 Multicelled, eukaryote, autotroph
 Green Algae (Charophytes)
o Cellulose cell wall & how its made (rosette complex)
o Chlorophyll a & b
o Cell division
o Peroxisome enzymes
o Flagellated Sperm
o Sporopollenin in spore walls
Chloroplast Structures
 Thylakoids – membranous sac
 Granum – stacks of thylakoids
 Stroma – internal fluid (DNA, ribosomes, & enzymes)
o NOT STOMA
Photosynthesis
 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
 Ingredients
o CO2 – enter thru stomata (stoma)
o Water – roots or across membrane
o Light – chlorophyll pigments (chlorophyll a & b, carotenoids)
 2 Parts
o Light Reactions (Photo)
 Converts light (solar) to chemical (ATP) energy
 Occurs in thylakoid membrane
 Photosystem II & I (PII & PI)
 Complex made of proteins, chlorophylls, carotenoids
 Photosystem II
 Chlorophyll a absorbs light
 Accessory pigments help (e.g. Chlorophyll b & carotenoids)
 Energy used to split water
o Makes ATP & O2 (by-product)
o Calvin Cycle (Synthesis)
 In stroma
 Series of enzymatic reactions requiring ATP
 CO2 (air) made into organic compounds (sugars)
 Sugar Use AFTER production…
o Sent to mitochondrion where ATP made
o Excess = starch
Beautiful Land
 Unfiltered sun (no water or plankton)
 More CO2 (air v. water)
 Nutrient-rich soil
 No herbivores & pathogens
 Land Problems
o Drying Out
 Sporopollenin – tough durable polymer covering spore
 Cuticle – waxy coat on plant
 Stomata – open & close
 Seed/pollen – protective coat
o Scarcity of water
 Mycorrhizae
 Roots & Vascular tissues
o Gravity
 Support – cell wall & stem
 Nutrient movement – xylem & phloem (vascular tissues)
4 Plant Traits
 Apical Meristems
o Regions of continuous cell division at tips of shoots/roots
o Sustained growth
 Epidermis
 Internal Tissues
 Leaves
 Alternation of Generations
o 2 multicellular forms…
 Sporophyte (2n) = all diploid cells
 Gametophyte (n) = all haploid cells
o In General
 Sporophytes (2n) make spores (n) by meiosis
 Spore becomes gametophyte
 Gametophytes (n) make gametes (n) by mitosis
 Gametes join = zygote (2n)
 Zygote grows = sporophyte
 Sporangia
o Multi-celled organ (in sporophyte) that makes spores
 Spores have sporopollenin wall
 Gametangia
o Multi-celled organ (in gametophyte) that makes gametes
 Antheridia – organ that makes & releases sperm
 Archegonia – organ that makes 1 immobile egg
3 Steps for Plant-kind
 Colonize Land
 Vascular Tissues
 Seeds
Plant Groups
 Nonvascular Plants
o No root, stem, leaf, seed, vascular tissues
o Gametophyte dominant
 Longer lived & bigger
o 3 Phylum…
 Moss, Liverwort, Hornwort
 Collectively called Bryophytes
 bryon = moss & phyton = plant

Seedless Vascular Plants
o 2 Phylum – Ferns & Club mosses
o Roots & leaves
o Vascular tissues
 Xylem
 Made of non-living cells
 Moves water & minerals
 Lignin surrounds cell wall
o Thick & strong polymer (i.e. wood)
 Phloem
 Made of living cells
 Moves sugars, amino acids, & organic products
o Sporophylls
 Modified leaf w/ sporangia
 Sori (on ferns) – cluster of sporangia on bottom of sporophyll
 Strobili (on pines) – cone-like structure made of groups of sporophylls
o Homosporous
 Produce one type of spore
 Makes both f. & m. gametophyte or bisexual (both sexes) gametophyte
 Bryophytes & Seedless Vasculars
 Seeded plants heterosporous
o Flagellated sperm
o Sporophyte dominant
 Small gametophyte
o First Forests
 Devonian & Carboniferous period
 Decaying forests = Coal
 More photosynthesis may have helped lower temps at end of Carboniferous period
Chapter 30: Hail the Seed
Seed
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Embryo
Nutrient supply
Allowed dormancy
Small & easy to transport
Protected – seed coat
o Like a mobile womb
5 Seed Plant Characteristics
 Heterosporous
o Megasporangium – make megaspores
 Become f. gametophyte
o Microsporangium – make microspores (i.e. pollen)
 Become m. gametophyte
 Reduced Gametophyte
o Sporophyte retains spore
 Gametophyte develops inside of spore
o Benefits…
 Protected from UV & desiccation
 Food from sporophyte
 Ovule
o Integument – protection
o Megasporangium (will make megaspore)
o Megaspore

Pollen
o aka Microspore
o Sporopollenin wall with male gametophyte inside
o Pollination
 Pollen delivered to ovule thru micropyle
 Pollen grain germinates
 Pollen tube forms
 Sperm discharged into ovule
 No water needed (or flagella)
 Seeds
o Embryo surrounded by seed coat (integument from ovule)
o Benefits…
 Dormant embryo
 Germinate in good conditions
 Food supply (f. gametophyte)
 Protective coat (dispersal aid)
Gymnosperms
 Naked seeds
 On sporophylls; usually grouped into strobili (cone)
 Adapted to dry conditions
o Wind Pollination
 3 Phylum
o Phylum Cycadophyta
 Cycads
 Large cones & palm-like leaves
 Thrived w/ dinosaur’s
o Phylum Ginkgophyta
 Ginkgo biloba – last species
 High tolerance to air pollution & a popular ornamental tree
o Phylum Coniferophyta
 Largest group of gymnosperms
 Most are evergreens & photosynthesize year round
Angiosperms
 Phylum Anthophyta
o Have seeds enclosed in fruit & flowers (for pollination)
o Two groups…
 Monocots
 One cotyledon
o Embryonic seed leaf
 Parallel venation
 Fibrous roots (no main root)
 Floral organs in 3’s (leaf, pedals)
 No secondary (lateral) growth
 e.g. Grasses & grains
 Eudicots
 Two cotyledons
 Netlike venation
 Taproot system
 Floral organs in 4’s or 5’s
 Have secondary growth
 e.g. Apple, oak, maple, pecan, walnut