Seed Plants - Kayleigh's

What protects the embryo in seeds?

Integument

What does the integument harden into?

Seed coat

What process does the megasporangium undergo inside the ovule?

Meiotic division

What type of spore is produced by the megasporangium?

Haploid megaspore

What does the megaspore divide by to produce?

Mitosis to produce a female gametophyte

What does the female gametophyte carry?

The female gamete, an egg

What does the seed contain for the embryo?

Food supply

What are male gametophytes?

Pollen grains.

How are male gametophytes transported to female gametophytes?

By wind or a pollinator.

Do male gametophytes require water for fertilization?

No, they do not need water.

Where do female gametophytes develop?

Within an ovule.

What encloses female gametophytes in angiosperms?

Diploid sporophyte tissue.

What is the ovary in relation to female gametophytes?

The ovule and protective tissue.

What does the ovary develop into?

Fruit.

What are gymnosperms?

Plants with 'naked seeds'.

How many lineages of seed plants do gymnosperms encompass?

Four of the five lineages.

What is one lineage of gymnosperms?

Coniferophytes.

What is another lineage of gymnosperms?

Cycadophytes.

What is another lineage of gymnosperms?

Gnetophytes.

What is the fourth lineage of gymnosperms?

Ginkgophytes.

What characteristic do all gymnosperms share regarding ovules?

All have ovules exposed on a scale.

Do gymnosperms have flowers and fruits?

No, they lack flowers and fruits.

What is the most familiar gymnosperm phylum?

Conifers

Name three types of conifers.

Pines, spruces, firs

What is the tallest living vascular plant?

Coastal redwood

What is the oldest living tree?

Bristlecone pine

In what type of regions are conifers typically found?

Colder temperate and sometimes drier regions

What are some important products sourced from conifers?

Timber, paper, resin, and taxol (anti-cancer)

How many species of pines are there?

More than 100 species

Where are all pine species found?

In the Northern hemisphere

What type of leaves do pines produce?

Tough needlelike leaves in clusters

What adaptations do pine leaves have to minimize water loss?

Thick cuticle and recessed stomata

What do pine leaves contain to deter insect and fungal attacks?

Canals with resin

Why are pines sometimes referred to as 'soft' wood?

Wood lacks some of the more rigid cell types found in other trees

What do male gametophytes develop from in pine trees?

Microspores in male cones by meiosis.

Where do male gametophytes grow in pine trees?

In lower branches.

Where do female pine cones form on a tree?

On the upper branches.

How do female pine cones compare in size to male cones?

Female cones are larger.

What do female pine cones have that male cones do not?

Woody scales.

How many ovules develop on each scale of a female pine cone?

Two ovules.

What is the name of the megasporangium contained in each ovule of a female pine cone?

Nucellus.

What do pollen cones produce?

Pollen grains

How are pollen grains carried to female pine cones?

By wind

What do the scales of each pine cone contain?

Ovules

Where does fertilization occur in female pine cones?

In the ovules on the scales

Where do seeds develop in female pine cones?

On the scales

What does the female gametophyte consist of at maturity?

Thousands of cells

How many archegonia does the female gametophyte have at the micropylar end?

2 to 6 archegonia

What does each archegonium contain?

A single large egg

How long do female cones usually take to mature?

Two or more seasons

What happens during the first spring of conifer pollination?

Pollen grains drift down between open scales

What draws pollen grains down into the micropyle?

The pollen grains themselves

What happens to the scales after pollen grains are drawn down?

The scales close

What are cycads?

Slow-growing gymnosperms of tropical and subtropical regions

What do the sporophytes of cycads resemble?

Palm trees

What type of cones do cycads produce?

Individuals make either pollen-bearing or ovule-bearing cones, not both

How heavy can female cones of cycads be?

Up to 45kg

How is sperm formed in cycads?

Sperm is formed in the pollen tube but released within the ovule to swim to the archegonium

Gnetophytes

only gymnosperms with vessels in their xylem

contain 65 species in three (unusual) genera

Welwitschia

Ephedra

Gnetum

What is the only living species of Ginkgophytes?

Ginkgo biloba

What type of sperm do Ginkgophytes have?

Flagellated sperm

Are Ginkgophytes dioecious?

Yes

Where do male and female reproductive structures form in Ginkgophytes?

On different trees

What are angiosperms commonly known as?

Flowering plants

What is enclosed in diploid tissue at the time of pollination in angiosperms?

Ovules

What does the carpel develop into in angiosperms?

Fruit

What is the oldest known angiosperm in the fossil record?

Archaefructus

How old is the oldest known angiosperm?

At least 125 million years old

Is Archaefructus likely to have been the first angiosperm?

Unlikely

What features does Archaefructus have?

Multiseeded carpels (fruits) and stamens

What floral structures does Archaefructus lack?

Sepals and petals

What are flowers in terms of plant structure?

Flowers are modified stems bearing modified leaves.

What is the term for the initial stage of flower development?

Primordium

What is the name of the stalk that supports a flower?

Pedicel

What does the pedicel expand to form?

A receptacle

How are flower parts organized?

In circles called whorls.

What is the outermost whorl of a flower called?

Sepals

What is the second whorl of a flower called?

Petals

What is the third whorl of a flower called?

Stamens (androecium)

What does each stamen consist of?

A pollen-bearing anther and a filament (stalk)

What is pollen in terms of plant reproduction?

The male gametophyte

What is the innermost whorl of a flower called?

Gynoecium

What does the gynoecium consist of?

One or more carpels

What does the gynoecium house?

The female gametophyte

What are the three major regions of the carpel?

Ovary, Stigma, Style

What is the function of the ovary in the carpel?

It is the swollen base containing ovules and later develops into a fruit.

What is the stigma in the carpel?

The tip where pollen lands.

What is the style in the carpel?

The neck or stalk connecting the stigma and ovary.

What is the role of a diploid megasporangium in an ovule?

It undergoes meiosis to produce 4 haploid megaspores.

What happens to the 4 haploid megaspores produced in an ovule?

3 of them disappear.

What does the nucleus of the remaining megaspore do?

It divides mitotically to form the female gametophyte.

What process produces 8 haploid nuclei in the female gametophyte?

Meiosis followed by three mitotic divisions of the megaspore nucleus.

What forms the central cell in the female gametophyte?

Cell wall forms around the polar nuclei.

What does the cell closest to the micropyle become in the female gametophyte?

The egg.

What do the two other cells in the group closest to the micropyle become?

Synergids.

What are the three cells at the opposite end of the female gametophyte called?

Antipodals.

What is the function of the antipodals in the female gametophyte?

They have no apparent function.

What do the integuments become in the seed development process?

The seed coat.

What is another name for the female gametophyte?

Embryo sac.

How many haploid nuclei are present in the female gametophyte?

8 haploid nuclei in 7 cells.