Page 518, Figure 25.9

Photosynthesisby

Purple Bacteria

Protists: •Domain Eukarya•Some Autotrophic (photosynthetic), some not•Aquatic•Greater part of life cycle as Haploid

Bryophytes

Gametophyte

Sporophyte

↑Liverwort

Moss →

Ferns & Fern Allies:

Fossil230 million years old China

Horsetail

The Seed PlantsThe Seed Plants

All plants that produce seeds are eitherGymnosperm = “naked seed”

or

Angiosperm = “covered seed”

Most gymnosperms occur in areas that are:

very cold (like the forests of Canada or Alaska)or

very dry (like deserts).

There aren’t many gymnosperms in tropical regions(which have warm temperatures,

and plenty of moisture).

Gymnosperm leaves

are usually tough and

leathery and shaped like:

Needles or

Scales or

Fronds

But there are some exceptions!

Ginkgo

Gnetum

Gymnosperms are usually perennials (live many years)…so are trees or shrubs.

Gymnosperms tend to be evergreen.

Although the leaves (be they needles, scales, etc.) do fall off, they do so continuously

instead of on any set schedule like you see with many deciduous (Angiosperm)

trees and shrubs.

In Gymnosperms, the reproductive structures are not called “flowers”

They are “cones”

Cones are usually unisex....Either male or female

Cones are often tough, and not very colorful,and can be:

papery or woody or berry-like

Most gymnosperms are wind-pollinated (and can cause allergies for some people).

…females produce a “pollination droplet”which catches pollen grains

to increase odds of fertilization.

Insect pollinators are not required.

Gymnosperms are generally considered to bemore ancient than Angiosperms

...this primarily comes from fossil evidence

Gymnosperms were the most common plantsduring the “Age of the Dinosaurs”

(65 to 250 million years ago)

....although there were some Angiosperms during this period

they didn’t become real abundant until about60 million years ago.

Mostly Cycads at that time

What advantage do Angiosperms have thatGymnosperms don’t have?

Angiosperms often have shorter life spans sothey can grow faster, and reproduce more

(before being eaten by animals).

This shorter life cycle would allow fasterevolution, because there are more generations.

Plus, when insect pollination came on the scenethere was more opportunity for plants to evolve

different mechanisms for attracting insects…..not only to pollinate them,

but also to eat and disseminate the fruit

This may help explain why there are only 760 species of Gymnosperms

while

there are about 250,000 species of Angiospermscurrently on the planet.

There are 4 phyla of Gymnosperm:

3) Ginkgo biloba (a single species)

2) the Cycads

1) the Conifers

4) the Gnetophytes

JuniperCypress

FirCedar

SequoiaRedwood

PineHemlock

LarchArborvitae

Yew

CONIFERS:CONIFERS:

CYCADS:

the palm-like gymnosperms

Ginkgo biloba

Gnetophytes:Gnetophytes:

EphedraWelwitschia

Gnetum

Only 1 species...it grows only in the desert of Namibia...can live 1000 years...gets its water mostly from fog

Welwitschia mirabilis

Durio zibethinus

An Angiosperm

Native to Borneo