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