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Seed and Flowers - Coggle Diagram
Seed and Flowers
Terms
Sepals are the outermost floral appendage.
Petals are located above the sepals on the receptacle.
Stamens occur above the petals.
Carpels, collectively, are the gynoecium.
Evolution of Ovule
Heterospory,Megasporangium enclosed in integuments,retention of megaspores w/in megasporangium, reduced # of megasporocytes/megasporangium to 1
Survival of 1 megaspore, Endosporic megagametophyte, Modification of megasporangium apex for microspores or microgametophytes, Embryo develop within megagametophyte
Survival of 1 megaspore
Megasporocyte undergoes meiosis 4 resulting daughter cells
3 megaspores degenerate
1 megaspore remains
Gymnosperm vs Angiosperm Ovule
Megasporangium is nutritious tissue = nucellus
Nested doll
Integument (1)
Megaspore wall
Megasporangium
Archegonium
Eggs
Angiosperm 2 integuments
Megasporangium = nucellus
Megasporocyte reduced to one
Megaspore reduced to one and retained
Megagametophyte = egg sac
Furniculum
Monocot vs Eudicot
Monocot One cotyledon = scutellum
Large amount of endosperm
Corn example
Integuments become seed coat
Eudicot 2 cotyledons
Large amount of endosperm
Integuments become seed coat
Bean example
Pollination syndrome
Abiotic: Anemophily (wind)
Hydrophily (water)
Biotic: Melittophily (bee)
Psychophily (butterfly)
Phalenophily (moth)
Myophily, sapromyophily (fly)
Ornithophily (bird)
Chiropterophily (bat)
Cantharophily (beetle)
Earliest seeds
Elkinsia polymorpha,4-5 lobes fused basal third, ~360mya,Late Devonian (W. Virginia), Pseudosporogonites quadrapartitus
Advantages of seeds
Increased independence from free water reproduction
Enabled colonization of drier upland habitats
Enabling advanced reproductive traits, Pollination drops
Embryo dormancy increase chance of offspring survival
Double Fertilization
Pollen tube grows down style, Generative cell divides into 2 sperm, Pollen tube ruptures inside synergid releasing sperm, One sperm fuses with egg, 2n diploid, Zygote
One sperm fuses with polar nuclei , 3n triploid, Endosperm
perfect, complete flowers
A flower is a stem with leaf-like structures.
Complete flowers have all four floral appendages: Sepals,sterile Petals, sterile Stamens, male fx Carpels,female fx, Incomplete flowers lack at least one appendage
Imperfect flowers
Lacking a whorl of sexual organs
Hermaphroditic = perfect
Monoecious = male flowers and female flowers on the same plant
Dioecious = male flowers on plant, female flowers on different plant
Male = androecious
Female = gynoecious
Ancestral flower, Based on molecular data, Bisexual, Radially symmetric, Multiple whorls of petals, Androecium 2+ whorls of anthers,Gynoecium 5+ carpels