Chapter 26/32: Seed Plants

BSC2011C Fall '25

What are some similarities seed plants have with vascular seedless plants?

Dominant sporophyte stage, xylem/phloem vascular tissue, true leaves stems and roots, true heterospory, and sporopollenin

What do female gametophytes produce?

Haploid eggs

What do male gametophytes (pollen) produce?

Sperm

What are sporophylls?

Modified leaves that produce sporangia

What are the newly derived traits in seed plants?

Gametophytes are reduced to microscopic structure inside sporophyte, both pollen and seeds are adapted for terrestrial living

Is reproduction or zygote viability water-dependent in seed plants?

NO

Once the egg is fertilized by the sperm, what does the 2n zygote develop into?

New sporophyte

What do seeds do to not compete with their parent?

Travel long distances

How many cells does a male gametophyte have?

Two cells

How are pollen dispersed?

Wind, water, or animals

What happens when pollen reaches the female gametophyte?

• Grows a pollen tube towards the egg

• Produces sperm that will travel down the tube and fertilize the egg

Who are gymnosperms sister taxa to?

Angiosperms

When did gymnosperms appear?

390 mya

What are the 4 categories of gymnosperms?

Conifers, Cycads, Ginkgophytes, Gnetophytes

When did angiosperms appear?

200 mya

Flowering plants are what kind of plant?

Angiosperms

Where do fertilization and embryo development happen in angiosperms?

Inside plant ovary

Who do angiosperms have mutualistic relationships with?

Animal pollinators and animal seed distributors

What are gymnosperms also known as?

Naked seeds

What are gymnosperm seeds covered by?

Sporophylls

Where are gymnosperm male/female gametes produced?

Separate cones but on same plant

Are gymnosperm heterospory or homospory?

Heterospory

What does monoecious mean?

Female and male cones on same plants

What does dioecious mean?

Female and Male cones in separate plants

What are gymnosperms pollinated by?

Wind only

What are tracheids in gymnosperms?

Perforated lignified cells that transport water and minerals (dominant xylem cell)

What are gymnosperms adapted to live without for part of the year?

Water

Where can gymnosperms live?

Cold, dry regions

Who are the dominant phylum of gymnosperms?

Conifers

What leaf shape do conifers have?

Needle-shaped leaf

Where can Conifers live?

Cold, dry weather and high altitudes

Which gymnosperm were the dominant phylum during the prehistoric era?

Cycads

Which gymnosperm is mistaken for palms?

Cycads

Where can cycads live?

Mild climate areas

Gingkophytes have what kind of leaf?

Fan-shaped

What are Gingkophytes last surviving species?

Gingko Biloba

What is the Gnetophyte phylogeny?

It’s unresolved

Where do Gnetophytes live?

Arid desert regions

In gymnosperms, the tree is what?

The sporophyte (2n) and is monoecious

Are conifers heterosporous or homosporous?

Heterosporous

What do microsporangia produce?

Male microspores

What do megasporangia produce?

Female megaspores

Where can microsporangia be found on conifers?

Male pollen cones

What are microsporocytes?

Diploid cells in the microsporangium

What do microsporocytes produce and by what process?

Haploid microspores via meiosis

After mitosis, what do microspores develop into?

Pollen

What is pollen surrounded by?

Sporopollenin

What cells are pollen made of?

Two haploid cells

What are the pollen’s two cells?

Generative cell and pollen tube cell

After mitosis, what does the generative cell produce?

Two haploid sperm cells

After mitosis, what does the pollen tube cell produce?

Pollen tube

What do male pollen cones contain?

Microsporangia

Are microsporangia diploid or haploid?

Diploid

What do microsporangia contain?

Microsporocytes

When microsporangia go through meiosis, what do they produce?

Four haploid microspores

Where are megasporangia located?

Female ovulate cones

Are megasporocytes diploid or haploid?

Diploid

Where are megasporocytes located?

Megasporangium

What do megasporocytes produce and by what process?

Four haploid cells via meiosis

How many megasporocyte offspring survive? What does the surviving cell(s) become?

1; becomes the female gametophyte

What does the female gametophyte produce?

Archegonium

What does the archegonium produce and by what process?

Haploid egg via mitosis

What does a new seed contain?

Seed coat from parent, nutritive tissue from female gametophyte, embryo tissue

Up to how long can conifer fertilization take?

Two years

Are angiosperm or gymnosperm the dominant terrestrial group?

Angiosperm

What are new traits in angiosperms?

Flowers and fruits

What do flowers do for the plant?

Ensure pollination and protects embryo

What do fruits do for the plant?

Embryo protection and dispersal

Are angiosperms monoecious, dioecious, or both?

Both

How do angiosperms get pollinated?

Wind, insects or mammals

What do angiosperm vessel cells in xylem tissue do?

More efficient way to conduct water

What are the four parts to an angiosperm?

Sepals, petals, carpels and stamen

What do sepals do?

They’re photosynthetic

What do petals do?

Attract pollinators with their colors

What can the carpel also be called?

Gynoecium

What is the carpel?

Female flower

What can the stamen also be called?

Androecium

What is the stamen?

Male flower

What does the carpel contain?

Stigma, style, ovary

What do perfect flowers contain?

Carpels AND Stamen

Are perfect flowers monoecious or dioecious?

Monoecious

What do imperfect flowers contain?

Carpels OR Stamen

Are imperfect flowers monoecious or dioecious?

Dioecious

What does the gynoecium produce?

Eggs

What are other names for the gynoecium?

Pistil, carpel, female flower

How many ovules do each ovary have?

One or more

What can ovaries also be called?

Megasporangia

What is the stigma’s function?

Place where pollen is deposited/trapped

What is the style?

Tube where the pollen tube grows

What do androecium produce?

Sperm

What are androecium also called?

Stamen, male flower

What is the stamen made up of?

Filament and anther

What is the filament?

Thin stalk that supports the anther

What is the anther?

Where microsporangia are located

What do microsporangia produce and by what process?

Haploid Microspores via meiosis

What do microspores develop into?

Pollen grains

In pollen production, what is the diploid sporophyte?

The plant

Are microsporangia homosporous or heterosporous?

Heterosporous

What are microsporocytes and where are they located?

Diploid cells in the microsporangium (correct)

What do pollen grains contain?

Two haploid cells surrounded by sporopollenin