Pollen tube enter ovule through micropyle 4 pollen

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pollen tube enter ovule through micropyle 4. pollen tube discharge sperm cells directly into embryo sac 5. faster-swimming sperm cell fuse with egg cell —> zygote —> embryo 6. slower sperm fuse with 2 nuclei of central cell ( triple fusion ) —> endosperm (food in seed) - double fertilization has been independently evolved 2 times (in Ephedra & anthophyta) - Traditional classification: monocots (monocotyledons) & dicots (dicotyledons) - dicot (only ~3% plants neither eudicots nor monocots) - Amborella ( ³Pč ) - most primitive extant species: Amborella - Nymphaeales ( !ÅK ) - most primitive extant species: water lily - superior ovaries - Austrobaileyales ( W éK ) - include Illicium ( ceD ) - Magnoliids ( W sÂ< ) - include Magnolia ( W D ) - Eudicots ( ´=µ¡Â< ) — 74% anthophyta - monocot: 24% anthophyta Structure developmental changes from flower —> fruit ovary fruit ovule seed ovary wall pericarp (fruit wall) sperm cell + egg cell —> zygote embryo sperm cell + polar nuclei endosperm integument testa (seed coat) / 20 66
BIOL1309 Notes - Evolutionary origin - Bennettitales - probably closest relationship - date: ~225 mya - earliest flower fossil: ~130 mya - Archaefructus - earliest fossil of flowering plant - 1 pollen aperture ( in Cycadophyta, Ginkgophyta, monocots) *** Eudicot Monocot flowering part usually 4X / 5X usually 3X pollen apertures / furrows (sites for pollen tubes to grow) cotyledons (foliage leaves) 2 1 leaf venation usually net-like usually parallel primary vascular bundles in stem ring form complex arrangement ‘true’ secondary growth often X eudicot & monocot adapt woody habit in a different way 3 1 / 21 66
BIOL1309 Notes Animalia - 35 phyla, >1,000,000 extant species - best known phylum: Chordata ( all vertebrates) — 5% - 95% — invertebrates Animalia (Invertebrate) - animals without backbone / other than vertebrae Porifera (Sponge) - 5,000-10,000 extant species - filter feeder (suspension feeding) - mainly marine - outer part ‘water in’, inner part ‘water out’ from an opening - skeleton —> sponge - spicules : needle-like skeleton - silica / CaCO 3 (calcium carbonate) / 22 66
BIOL1309 Notes Animalia (Invertebrate) Phylum: Cnidaria - Main characteristics - ~9,000 species - exclusively aquatic animals (mainly marine, some freshwater) - radial symmetry - circle of tentacles surrounding central mouth - tentacles used for food capture - similar body parts are arranged & repeated around a central axis - X head / front / back - life-form: polymorphism - polyp form (sessile) - medusa form (free-living / swimming) - alternating sequence of polyp & medusa - body structure — diploblastic (2 cell layers) - outer ectoderm - jelly-like mesoglea - inner endoderm - simple gut cavity - open @ 1 end form a mouth - no centralized brain - Unique characteristics - carnivores - cnidocytes — specialized stinging cells containing nematocysts - nematocysts - secretory structures - emit long threads explosively - for defense & food capture - on ectoderm , ^^ in tentacles - Class: Hydrozoan - mainly in polyp form - medusa phase is present only in some species - classification recently changed - small marine - paraphyletic - hydromedusae - <6cm diameter - velum ( ) along bell margin (distinguish feature with true jellyfish) -

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