Chapter 30

360 mya, seed plants evolved 13,000 years ago, humans began

domesticating wheat, corn, rice, and bananas

The gametophytes of seed plants are too small to be seen with the naked eye; and are protected by a seed.

Two main types: gymnosperms and angiosperms

The female reproductive structure is called an ovule

The male reproductive cell is called pollen. During pollination, a pollen grain combines

with an ovule... This becomes a zygote, which becomes an

embryo, which develops into a seed: consisting of the embryo, a food supply and a protective coating.

Resist harsh environments Disperse more widely Can survive extremes in heat and moisture Multicellular complex seeds have their own

nutrient supply Can remain dormant for days, months, or

years

Gymnosperms are vascular plants that bear naked seeds (seeds not enclosed in ovaries) in cones, aka “conifers”

There are 4 gymnosperm phyla you need to know:

Cycadophyta Ginkophyta Gnetophyta Coniferophyta

Phylum Cycadophyta = cycads Large cones, palm like leaves Thrived during the time dinosaurs were

alive

Phylum Ginkophyta = Gingko Biloba “Maidenhair tree” Fanlike leaves, turn gold in Autumn Ornamental trees that withstand pollution

Phylum Gnetophyta = gnetophytes Live in tropics (or desert) Vary greatly

Phylum Coniferophyta = conifers Largest phyla, includes cypresses,

redwoods, fir, juniper, sequoia, pine, yew

Grow in taiga in Northern Hemisphere Evergreen, retain leaves throughout

year

Angiosperms are flowering plants They are vascular plants with seeds

enclosed in ovaries (flowers or fruits) Only one phylum = Anthophyta

Flowers are specialized structures for sexual reproduction. Sepals are modified green petals that enclose the flower

before it opens Petals are brightly colored and attract pollinators

Stamens are male reproductive organs that produce pollen (male gametophytes)

They consist of a stalk called a filament, and an anther at the top where pollen is made.

Carpels (or pistils) are the female reproductive organs of flowers and produce ovules (eggs).

The ovary is the base which contains ovules, the style is the stalk, and the sticky top that receives pollen is called the stigma.

Fruits are mature, ripened ovaries (after pollination has occurred).

The thickened wall of the ovary is called the pericarp.

Fruits can be: Fleshy or dry Oranges,

strawberries, grapes

Beans, nuts, grains Fruits: Disperse seeds Are nutritious,

sweet, and colorful

Eggs + Sperm = Fertilization making a zygote

Zygote becomes an embryo then a seed

Seed is planted and becomes a flower

Flowers produce eggs and sperm via meiosis

Angiosperms are divided into 4 main categories:

Basal Angiosperms Magnoliids Monocots Dicots (Eudicots)

Basal angiosperms are the oldest flowers (first to evolve)

Include water lilies and star anise

Include 8,000 plants: magnolias, laurels, and black pepper plants

¼ of angiosperms In their seeds they have only one little seed

leave, called a cotyledon Include orchids, dates, lilies, barley

Dicots or eudicots: 2/3 of angiosperms Have 2 little cotyledons Very diverse: poppies, oak, roses, peas,

zucchini

Monocots Dicots

One cotyledon Parallel Leaf Veins Scattered Vascular

Tissue Branched roots Pollen grains with one

opening Petals in multiples of 3

Two cotyledons Netlike leaf veins Vascular Tissue

arranged in rings One main root,

“taproot” Pollen grains with 3

openings Petals in multiples of 4

or 5

The evolution of angiosperms and animals influenced each other

Insects (like bees) pollinate flowers and collect nectar and pollen to make honey

Birds (like hummingbirds) pollinate flowers and drink nectar

Nocturnal animals (like bats) pollinate cacti and get nectar.

6 crops: wheat, rice, corn, potatoes, cassava, and sweet potatoes make up 80% of all calories consumed by humans

Tea and coffee, cocoa and chocolate come from seed plants

Cloves, saffron, vanilla, pepper, mustard, cumin, basil, sage, mint and cinnamon (bark) do too

Wood and paper Medicine like aspirin and cancer drugs

Deforestation (for lumber and agriculture and grazing animals)-all due to population growth

Loss of plant diversity causes loss of insect and animal diversity

Will cause extinction, climate change, and missed discovery of potential medicine