PLANT DIVERSITY 2

Plant Kingdom• Bryophytes

• Ferns

• Gymnosperms

• Angiosperms

Vascular

Seed Plants: -- Have seeds -- Have pollen (containing sperm)

seedless

• PLANT KINGDOM (major groups)– MOSSES (“non-vascular”)– FERNS– GYMNOSPERMS (conifers)– ANGIOSPERMS (flowering plants)

seedless

Vascular

Seed Plants: -- Have seeds -- Have pollen (containing sperm)

Seed Plants Have:• Vascular Tissue:

– Functions as in ferns• Pollen: a structure that surrounds/contains sperm

– Allows transport of sperm without water– Protects the sperm from drying out– Adaptations to life on dry land, can reproduce w/o water

• SEEDS: a structure surrounding/containing the embryo– Protects the embryo (from drying out)– Provides food/nourishment for embryo– Promotes dispersal of embryo away from established

plants—reduces competition

Pollen and Seeds are adaptations to dry land or help increase reproductive success.

Pine Trees & firs are Gymnosperms(specifically conifers)

Other Gymnosperms (specifically conifers): Junipers (cypress and cedars)

Cycads are Gymnosperms too

And Ginko Trees

Gnetophytes including Ephedra are also Gymnosperms

Gymnosperm Characteristics

• Vascular Tissue and Roots• can grow large and in relatively dry places

• POLLEN: – Allows fertilization/reproduction and dispersal

without water

• SEEDS: – protects the embryo from drying until it can

germinate and promotes dispersal

We will look closer at pine trees as examples of typical gymnosperms

Pine Trees have……

Needles

(leafs)

Cones

--reproductive structuresFemale cone

male cones

Reproduction, Pollen, and Seeds in Pines• Male Cones make pollen• Pollen is dispersed by wind

wings

Reproduction, Pollen, and Seeds in Pines• Female cones make ovules containing the egg

ovulescales

Reproduction, Pollen, and Seeds in Pines• Ovule w/ egg turns into seed after fertilization• Pine seeds have wings and are wind dispersed

Wings on pine seeds

What is an Angiosperm?

A plant with flowers

...even when the flowers aren’t obvious

Angiosperms with non-showy flowers are typically wind pollinated so large colorful flowers are not needed to attract pollinators and would get in way of wind

Conspicuous flowers use animal pollinators:the key to Angiosperm success

Angiosperm Characteristics• Vascular Tissue

– Can grow large and in relatively dry places• Pollen

– Frequently dispersed by animals—pollinators– But also wind (and occasionally water dispersed)

• Seeds– Surrounded by fruit promotes dispersal of embryo

• FLOWERS– Attract pollinators (color & scent)– Reward pollinators (nectar & pollen)– Put sex parts in same place to promote pollinations/fertilization

• FRUIT—structure that surrounds the seed– Can provide protection to seed– Disperses the seed (MAIN IDEA BEHIND BENEFIT OF FRUIT)

• Frequently utilizes animals• Sweet, fragrant, colorful• Dry and “clingy”

– But also wind (and occasionally water dispersed)

Angiosperm pollen• Made by anthers, allows sperm to travel to egg w/o water

Sperm nuclei and pollen tube

Fruit With Seed• After fertilization:• Ovule seed• Ovary of flower fruit

Fruit with seed

Dry Fruit

Fruit v. Vegetable

Tomato:fruit or vegetable?

…….would you put it in a fruit salad?

Tomato:fruit or vegetable

• Botanically it is a fruit• Typically used as a vegetable for cooking/culinary purposes• US Supreme court decided that the tomato shall be considered a

vegetable in Nix v. Hedden (1893) for Tariff Act of 1883

• The 1887 a case came before the supreme court.• John Nix sued the collector of port of New York to recover duty (tax)

paid on imported vegetables, but they argued they should not have paid because the tomato is a fruit

• The U.S. Supreme Court decided on May 10, 1893 that the tomato is a vegetable, based on them generally being served with dinner as was typical for vegetables where as fruit were often used as desserts and not part of main course.

• the court did not purport to reclassify the tomato for botanical or other purpose

Flowers: structure and function

Floral Parts:

•Sepals

•Petals•Stamen/anthers: (produce pollen w/ sperm)

•Pistil (carpel): ovary (containing egg)

Additional Terms

• Dioecious: separate male and female individuals/plants (organisms)

• Monecious: male and female parts on same individual plants (organism)

Dicots v. Monocot

Monocot• Seed

– One part/cotyledon

• Leaves– parallel venation

• Flower parts– Petals in multiples of

three

Dicot• Seed

– two parts/cotyledons

• Leaves– netted venation

• Flower parts– Petals in 4’s or 5’s

Embryos Leaf venation Stems

MonocotCharacteristics

Onecotyledon

Veins usuallyparallel

Vascular tissuescattered

Root systemusually fibrous(no main root)

Pollen grainwith oneopening

Floral organsusually inmultiplesof three

Floral organsusually in

multiples offour or five

Pollen grainwith threeopenings

Taproot(main root)

usually present

Vascular tissueusually arranged

in ring

Veins usuallynetlike

Twocotyledons

EudicotCharacteristics

Roots Pollen Flowers