Continuing Trends in Plant Evolution
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Transcript of Continuing Trends in Plant Evolution
Continuing Trends in Plant Continuing Trends in Plant EvolutionEvolution
• Ultimate reduction of water-dependent gametophyte* double fertilization
• Vascular tissue – improved more• Herbaceous habit• Secondary compounds• Flowers – more efficient pollen• Fruits – seed dispersal
Green: all these are in sporophyte
Flowers & fruitsFlowers & fruits• Flowers attract &
encourage pollinators
• Fruits aid in dispersal of seeds
Flowers & fruitsFlowers & fruits
• Flower a major advancement• Flower parts are modified leaves
* Sepals – protect flower in bud* Petals – attract pollinators* Stamens – produce pollen* Pistil(s) – produce and protect ovules
• Fruit develops from ovary
FlowerFlower Pistil
FruitFruit
Ovary
Ovule♀
Pollen grain♂
Ferti
lizati
on (d
oubl
e)Gametophytes
Seed dispersal
& germinationMeio
sis
Mei
osis
Sporophyte
Flowering Flowering plant life cycleplant life cycle
Evolution of flower & fruitEvolution of flower & fruit• First fossils: late Jurassic period of Mesozoic era• Diversified during Cenozoic era• Coevolution with pollinators
Orchid
Fruits
Flowering plantsFlowering plants survey survey
• “Angiosperms” (= covered seed)• Phylum Anthophyta
* Magnolias – primitive* Monocots – grasses, palms, lilys, etc.* Eudicots – everything else
Magnolia
MonocotsMonocots
Grass family, Andropogon
Oriental lily
PearPyrus
Eudicot
Vaccinium deliciosum
Eucalyptus
Largest flowerRafflesia and friends
Smallest flowerWater Meal, Wolffia
What does this pollinate???
Large, hairy bee fly from Stehekin