Plants - Reproduction

Question 1

How do angiosperms reproduce sexually?

Answer 1

adapted mechanisms to attract animal pollinators that help them reproduce sexually by transferring their pollen

Question 2

Humans have used ……. and ……. to modify wild angiosperms into modern crop species

Answer 2

artificial selection / genetic engineering

Question 3

What is the dominant generation in angiosperms?

Answer 3

Sporophytes, they are larger, more conspicuous, and longer-lived than gametophytes

Question 4

The angiosperm life cycle is characterized by “three Fs”:

Answer 4

Flowers, double Fertilization, and Fruits

Question 5

Spores divide by …… and form ……., which are …….. plants that produce ………. by ……..

Answer 5

mitosis / gametophytes / haploid (n) / gametes (sperm and eggs) / mitosis

Question 6

Flowers

Answer 6

reproductive shoots of the angiosperm sporophyte

Question 7

Receptacle

Answer 7

A part of the stem flowers attach to

Question 8

Flowers consist of four floral organs:

Answer 8

carpels, stamens, petals, and sepals

Question 9

Stamens and carpels are

Answer 9

sporophylls (leaves specialized for reproduction); sepals and petals are sterile modified leaves

Question 10

A carpel (megasporophyll) has a

Answer 10

long style with a sticky stigma on top that captures pollen

Question 11

At the base of the style is a(n) ……. containing one or more …….

Answer 11

ovary / ovules

Question 12

Fertilized ovules produce

Answer 12

seeds

Question 13

Pistil

Answer 13

A single carpel or group of fused carpels

Question 14

A stamen (microsporophyll) consists of a filament topped by an

Answer 14

anther

Question 15

The anther contains ………. that produce …….

Answer 15

microsporangia (pollen sacs) / pollen

Question 16

Sepals

Answer 16

structures that resemble leaves; they enclose and protect unopened floral buds

Question 17

Petals

Answer 17

typically brightly colored to attract pollinators

Question 18

Complete flowers

Answer 18

contain all four floral organs

Question 19

Incomplete flowers

Answer 19

flowers lack one or more floral organs, for example, petals or stamens

Question 20

Sterile flowers lack

Answer 20

both stamens and carpels

Question 21

Unisexual flowers lack

Answer 21

either stamens or carpels

Question 22

Inflorescences

Answer 22

Clusters of flowers

Question 23

Pollination

Answer 23

the transfer of pollen from anthers to stigma

Question 24

Pollination can occur by

Answer 24

wind, water, or animals

Question 25

What type of species release large amounts of smaller-sized pollen?

Answer 25

Wind-pollinated species (e.g., grasses and many trees)

Question 26

About ..... of angiosperm species are wind-pollinated

Answer 26

20%

Question 27

Wind-pollinated angiosperms tend to produce small, inconspicuous flowers that lack ...... or ...... and release large amounts of .......

Answer 27

nectar / scent / pollen

Question 28

About ..... of all angiosperms require insects for pollination

Answer 28

65%

Question 29

Bee-pollinated flowers are primarily ....... or ....... , butterfly-pollinated flowers are ............., and moth-pollinated flowers are usually ...... or .......

Answer 29

yellow / blue / brightly-colored / white / yellow

Question 30

Bat-pollinated flowers are

Answer 30

light-colored and aromatic

Question 31

Bird-pollinated flowers are usually

Answer 31

large and bright red or yellow, have little odor, and produce large quantities of nectar

Question 32

The petals of bird-pollinated flowers are often fused into a

Answer 32

floral tube that fits the curved beak of the bird

Question 33

Coevolution

Answer 33

the joint evolution of two or more interacting species in response to selection imposed by each other

Question 34

The shapes and sizes of flowers often correspond to the

Answer 34

pollen-transporting parts of their animal pollinators

Question 35

The angiosperm life cycle includes

Answer 35

1. Gametophyte development 2. Sperm delivery by pollen tubes 3. Double fertilization 4. Seed development

Question 36

Gametophytes have evolved to become reduced in size and wholly dependent on the ......... for ........

Answer 36

sporophyte / nutrients

Question 37

Angiosperm gametophytes are microscopic, and their development is hidden by ....... .........

Answer 37

protective tissues

Question 38

The embryo and its food supply are enclosed by a hard, protective

Answer 38

seed coat

Question 39

The seed dehydrates and enters a state of

Answer 39

dormancy

Question 40

A mature seed is only about

Answer 40

5–15% water

Question 41

In some eudicots, such as the garden bean, the embryo consists of the

Answer 41

embryonic axis attached to two fleshy cotyledons

Question 42

Below the cotyledons, the embryonic axis is called the .......... and terminates in the ............

Answer 42

hypocotyl / radicle (embryonic root)

Question 43

Seed dormancy increases the chances that

Answer 43

germination will occur at a time and place most advantageous to the seedling

Question 44

Seed dormancy breaks when

Answer 44

environmental conditions are right for growth

Question 45

Germination is followed by growth of

Answer 45

stems, leaves, and roots and eventually by flowering

Question 46

Imbibition

Answer 46

The uptake of water due to the low water potential of the dry seed, germination depends on it.

Question 47

The ........ emerges first; the developing root system ..... ..... ..... and provides water for ...... .......

Answer 47

radicle (embryonic root) / anchors the plant / cell expansion

Question 48

In many ......., a hook forms in the hypocotyl, and growth pushes the hook above ground

Answer 48

eudicots

Question 49

........ causes the hook to straighten and pull the cotyledons and shoot tip up

Answer 49

Light

Question 50

In some ........., the coleoptile pushes up through the soil, creating a tunnel for the shoot tip to grow through

Answer 50

monocots

Question 51

Flowers are typically synchronized to appear at a specific time of the year. Why?

Answer 51

This promotes outbreeding—reproduction between two genetically distinct individuals

Question 52

Flowering is triggered by a combination of

Answer 52

environmental cues and internal signals

Question 53

A developmental switch from vegetative to reproductive growth occurs in the

Answer 53

apical meristem

Question 54

Fruit

Answer 54

- The mature ovary of a flower - Protects the enclosed seeds and aids in seed dispersal by wind or animals

Question 55

Fruit only develops in response to

Answer 55

hormonal changes triggered by fertilization

Question 56

In some fruits, the ovary wall

Answer 56

dries out at maturity; in others the ovary wall remains fleshy

Question 57

A fruit usually ripens at the same time that the

Answer 57

seeds complete development

Question 58

In dry fruits, ripening involves

Answer 58

aging and drying of tissues

Question 59

Fleshy fruits change from green to

Answer 59

another contrasting color

Question 60

Sugar is produced to

Answer 60

attract animal dispersers

Question 61

Fruits are classified based on

Answer 61

their developmental origin

Question 62

Simple fruits

Answer 62

develop from a single or several fused carpels

Question 63

Aggregate fruits

Answer 63

result from a single flower with multiple separate carpels

Question 64

Multiple fruits

Answer 64

develop from a group of flowers called an inflorescence

Question 65

Accessory fruits

Answer 65

contain other floral parts in addition to ovaries

Question 66

Tumbleweeds

Answer 66

break off at the ground and tumble across the terrain, scattering their seeds

Question 67

Fragmentation

Answer 67

Separation of a parent plant into parts that develop into whole plants

Question 68

Apomixis

Answer 68

the asexual production of seeds from a diploid cell

Question 69

Advantages of Asexual Reproduction

Answer 69

- Do not require pollinators to produce offspring - All progeny are genetically identical to the parent, compared to half with sex - If environment stable, same is good - When asexual progeny arise from mature vegetative fragments, it is called vegetative reproduction - These progeny are more resilient than the fragile seedlings that germinate from seeds - Production of enormous numbers of seeds compensates for odds against individual survival

Question 70

Disadvantages of Asexual Reproduction

Answer 70

- Lack of genetic variation makes them vulnerable to local extinction if environment changes - Sexual reproduction generates genetic variation that makes evolutionary adaptation possible - Seed production also facilitates long distance dispersal to escape catastrophic environmental change - Some sexual plants can self-fertilize to ensure that every ovule will develop into a seed

Question 71

Selfing

Answer 71

reduces genetic diversity among offspring