BIO 1B 3.2 Seed Plants

What are progymnosperms?

The first naked seed plants and a transitional group between spore-bearing and modern seed plants.

How did progymnosperms reproduce?

Through fern-like reproduction.

What is the current status of progymnosperms?

They are all extinct.

What is the difference between homosporous and heterosporous plants?

Homosporous plants produce one type of spore; heterosporous plants produce microspores (male) and megaspores (female).

What is the purpose of pollen grains?

To carry male gametophytes and deliver male nuclei to female gametophytes without needing water.

What do seeds provide for a developing embryo?

Protection and nutrients.

What is seed dormancy?

A survival strategy allowing seeds to endure harsh conditions and aiding in the dispersal.

What is a seed coat?

The protective outer layer of a seed.

What is endosperm?

Food-rich tissue that nourishes a developing seedling.

What are conifer leaves adapted for?

Reducing water loss and preventing branch breakage from snow.

What is a gymnosperm?

A plant with 'naked seeds' not enclosed in an ovary, protected by sporophylls.

What are the living groups of gymnosperms?

Coniferophytes, Cycadophytes, Gnetophytes, Ginkgophytes.

How do sporophytes and gametophytes interact in gymnosperms?

Sporophytes are dominant while gametophytes are microscopic and dependent.

What do gymnosperms lack?

Flowers and fruits.

What is the role of female strobili?

To produce megagametophytes (seed cones).

What do male strobili produce?

Microgametophytes (pollen cones).

What are some key characteristics of conifers?

Mostly monoecious, needle-like leaves, evergreen, and 'soft wood' containing tracheids.

Describe the process of meiosis in seed cones.

Megasporocytes in the ovule undergo meiosis, producing haploid megaspores, one of which develops into the megagametophyte.

What is an ovule?

A structure developing within the ovary that contains the female gametophyte.

What is a micropyle?

The opening in the ovule where the pollen enters for fertilization.

Describe the process of meiosis in pollen cones.

Microsporocytes undergo meiosis to produce haploid microspores, which develop into pollen grains, each containing four haploid cells.

Where are cycads typically found?

In tropical and subtropical regions.

During which periods were cycads dominant?

Mesozoic and Jurassic periods.

Are cycads dioecious or monoecious?

Dioecious.

What is unique about Ginkgo biloba?

It is the only extant species of ginkgos with fan-shaped leaves.

What are some features of Gnetophytes?

Angiosperm-like features such as vessels in xylem, double fertilization, and fruit-like ovule coverings.

What is the function of double fertilization in angiosperms?

To form a zygote and a triploid endosperm for embryo nourishment.

What are basal angiosperms?

Plants that branched off before the separation of monocots and eudicots.

What are the characteristics of monocots?

One cotyledon, parallel leaf veins, scattered vascular tissue, and fibrous roots.

What are the characteristics of dicots?

Two cotyledons, branched leaf veins, vascular bundles in a ring, and secondary growth.

Examples of monocots include...

Palm trees, corn, wheat, and grasses.

Examples of dicots include...

Roses, sunflowers, and oak trees.

What is double fertilization?

Involves one sperm fertilizing the egg and another fusing with polar nuclei to create the endosperm.