Biology 200 Chapter 23: Angiosperms

Comprehensive practice questions covering angiosperm biology, reproduction, classification, and pollination ecology based on the lecture notes.

What is the primary defining characteristic of angiosperms?

They are flowering plants with seeds enclosed in a carpel.

What structure does the carpel resemble in its evolutionary origin?

A leaf that has folded over and fused at the margins.

What are the components of a pistil?

A single carpel, or two or more united carpels.

Into what structures do the ovule and ovary develop, respectively?

The ovule develops into a seed and the ovary becomes a fruit.

To which phylum do all angiosperms belong?

Phylum Magnoliophyta.

What are the two large classes within Phylum Magnoliophyta?

Magnoliopsida (Dicots) and Liliopsida (Monocots).

What is the botanical definition of a flower?

A modified stem bearing modified leaves.

What are the features of the most primitive flowers?

Long receptacle, many separate spirally arranged parts not differentiated into sepals and petals, and numerous flattened stamens and carpels.

Approximately how many species of angiosperms are parasitic?

$4,000$ species.

How do parasitic angiosperms obtain food and water from their hosts?

They intercept food and water in the xylem and phloem of the host.

Give two examples of saprophytic plants mentioned in the text.

Certain orchids and the Snowplant.

In the alternation of generations in angiosperms, which stage is dominant?

The sporophyte.

What does a mature male gametophyte consist of?

A germinated pollen grain with $3$ nuclei.

Where does the diploid megasporocyte differentiate?

Within the ovule.

What is the result of meiosis in a megasporocyte?

$4$ haploid megaspores, three of which degenerate.

Into what do the outer two layers of the ovule differentiate?

Integuments, which later become the seed coat.

What name is given to the pore at one end of the ovule?

The micropyle.

How many nuclei and cells make up a typical mature female gametophyte?

$8$ nuclei and $7$ cells.

What are the three types of cells found in a mature female gametophyte besides the egg and central cell?

Two synergids and three antipodals.

Where does the formation of male gametophytes take place?

In the anthers.

What cells in the anther undergo meiosis to produce microspores?

Microsporocyte cells.

What two cells are formed when a microspore divides by mitosis?

A small generative cell and a larger tube cell.

What is the vegetative nucleus?

The nucleus of the tube cell.

What is the name of the finely sculptured outer layer of a pollen grain wall?

The exine.

What is the eventual function of the generative nucleus?

It divides to produce two sperm.

Define pollination.

The transfer of pollen grains from anther to stigma.

Specify the process of self-pollination.

Pollen grains germinate on the stigma of the same flower.

Where does the generative cell divide into two sperm during germination?

While lagging behind the vegetative nucleus as the pollen tube grows.

Upon entering the female gametophyte, what cell does the pollen tube typically destroy?

A synergid.

Describe the process of double fertilization.

One sperm unites with the egg to form a zygote, and the other unites with the central cell nuclei to produce a triploid endosperm nucleus.

What is the function of endosperm tissue?

It serves as nutritive tissue for the embryo.

In which plants does the endosperm become an extensive part of the seed?

In some monocots, such as corn and other grasses.

What happens to the endosperm in most dicots?

It is absorbed into the cotyledons.

In lilies, what is the resulting ploidy of the endosperm nucleus after fertilization?

$5x$.

Define apomixis.

The development of an embryo from a diploid cell of the ovule without the fusion of gametes.

Define parthenocarpy.

The development of fruits from ovaries with unfertilized eggs, resulting in seedless fruits.

When does the fossil record suggest flowering plants first appeared?

About $160$ million years ago during the late Jurassic.

What are the common evolutionary trends in flower specialization regarding part number and arrangement?

Parts have become fewer, some have fused, and spiral arrangements have compressed into whorls.

What is a regular flower?

A flower that is radially symmetrical.

What defines a hypogynous flower?

A flower with a superior ovary, where the ovary is produced on top of the receptacle.

What defines an epigynous flower?

A flower with an inferior ovary, where the receptacle or other parts are fused to and grow around the ovary.

What is a perigynous flower?

A flower where parts are attached to a floral tube (fused petals) that is not attached to the ovary.

Distinguish between a complete and an incomplete flower.

A complete flower has a calyx, corolla, stamens, and pistil; an incomplete flower is missing one or more of these.

Distinguish between a perfect and an imperfect flower.

A perfect flower has both stamens and a pistil; an imperfect flower is missing one of these.

Define monoecious species.

Species that have both male and female imperfect flowers on the same plant.

Define dioecious species.

Species where a plant bears only male flowers and other plants bear only female flowers.

What colors are typically associated with bee-pollinated flowers?

Brightly colored, mostly blue or yellow.

What specific light spectrum can bees see that humans cannot, aiding in pollination?

UV light.

What are the characteristic features of beetle-pollinated flowers?

Strong, yeasty, spicy, or fruity odors, and white or dull colors.

How are fly-pollinated flowers characterized?

They smell like rotten meat and are dull red or brown.

What are features of bird-pollinated flowers?

Bright red or yellow colors, copious nectar, long floral tubes, and little to no odor.

Describe bat-pollinated flowers.

Open at night, dull in color, large or in ball-like inflorescences, and found primarily in the tropics.

What are pollinia?

Pollen grains produced in little sacs with sticky pads at the base, characteristic of orchids.

What is the genus Ophrys noted for in terms of pollination?

Having a modified petal that resembles a female bumble bee or wasp to trick males into copulating with the flower.

What is a herbarium?

A library of dried, pressed plants, algae, and fungi that are arranged and labeled.