Angiosperms - Cycle 3

Question 1

Methods of Pollination: Abiotic Pollination

Answer 1

• Among abiotically pollinated species, 98% rely on wind and 2% on water.
• Since their reproductive success does not depend on attracting pollinators, there has been no selective pressure favoring colorful or scented flowers.
• Wind circulates but water ends so that’s why it relies on wind more

Question 2

Methods of Pollination: Biotic Pollination

Answer 2

• Most angiosperm species depend on insects, birds, or other animal pollinators to transfer pollen directly from one flower to another
• Pollination by: flies, bees, birds, bats, and moth/butterfly

Question 3

Coevolution

Answer 3

• The joint evolution of two interacting species, each in response to selection imposed by the other, is called coevolution.
• Ex: Some species have fused flower petals that form long, tubelike, structures bearing nectaries tucked deep inside.

Question 4

Parts of the Flower: Petals

Answer 4

Attract pollinators

Question 5

Parts of the Flower: Sepals

Answer 5

Protect the bud as the flower develops

Question 6

Parts of the Flower: Carpels

Answer 6

The female portion

Question 7

Parts of the Flower: Stamens

Answer 7

The male portion

Question 8

Parts of the Flower: Stamens, Anther

Answer 8

Houses pollen grains

Question 9

Parts of the Flower: Stamens, Filament

Answer 9

Supports the anther

Question 10

Parts of the Flower: Carpel, Stigma

Answer 10

Recieves the pollen

Question 11

Parts of the Flower: Carpel, Style

Answer 11

Pathway for pollen

Question 12

Parts of the Flower: Carpel, Ovary

Answer 12

Structure that will become fruit

Question 13

Parts of the Flower: Carpel, Ovule

Answer 13

Structure that will become seed

Question 14

Complete Flower

Answer 14

Possess sepals, petals, stamens, and carpels

Question 15

Incomplete Flower

Answer 15

Lack one or more of these components

Question 16

Perfect Flower

Answer 16

Posses both stamens and carpels.

Question 17

Imperfect Flower

Answer 17

Posses either stamens (staminate) or carpels (carpelate) but not both.

Question 18

Forms of Pollination: Self-Pollination

Answer 18

The pollination of a flower by pollen from the same flower or from another flower on the same plant

Question 19

Forms of Pollination: Cross-Pollination

Answer 19

Occurs when pollen grains are transferred to a flower from a different plant.

Question 20

Alternation of Generations

Answer 20

• Describes the life cycle of a plant as it alternates between a sexual phase and an asexual phase
• The sporophyte produces flowers. Inside the flower, diploid cells undergo meiosis to produce haploid microspores and megaspores. These cells, in turn, develop into the gametophytes that produce sperm and egg by mitosis.

Question 21

Alternation of Generations Types: Sporophyte Generation

Answer 21

• Non-sexual stage in plants
• Plants grow and develop to form flowers
• The flowers produce reproductive cells called spores

Question 22

Sporophyte Generation Types of Spores: Microspores

Answer 22

may become the male gametophyte

Question 23

Sporophyte Generation Types of Spores: Megaspores

Answer 23

may become the female gametophyte

Question 24

Alternation of Generations Types: Gametophyte Generation

Answer 24

• This is the sexual stage in plants.
• Development of sperm cells from male gametophyte (pollen grains)
• Development of egg cells from female gametophyte.

Question 25

Sexual Reproduction

Answer 25

• In this life cycle, a diploid (2n) sporophyte alternates with a haploid (n) gametophyte
• The sporophyte (2n) produces haploid spores by meiosis. The spores develop into gametophytes.
• The gametophytes (n) produce gametes

Question 26

Diploid

Answer 26

(2n) is a cell organism that has paired chromosomes, one from each parent

Question 27

Haploid

Answer 27

(n) is a cell organism that contains a single set of chromosomes

Question 28

Mitosis

Answer 28

• For growth and development

- Produces two diploid (2n) somatic cells that are genetically identical to each other.

Question 29

Meiosis

Answer 29

Produces four haploid (n) gametes that are genetically unique from each other

Question 30

Microspore Develops into Sperm

Answer 30

• Four microscopes are produced via meiosis. Each one becomes a pollen grain.
• A pollen grain at first consists of two cells
• The larger cell will eventually produce a pollen tube
• The smaller cell divides, either right away or later, to become two sperm

Question 31

Megaspore Develops into Embryo Sack

Answer 31

• Four megaspores are produced via meiosis but only 1 survives
• The remaining cell divides 3 times through mitosis
• Embryo sac is developed containing seven celled containing a single egg cell

Question 32

Eight-Nucleate, Seven Cell Female Gametophyte.

Answer 32

• From the 8 generated haploid cells:
  
  • 2 haploid cells move in the middle and join forming a diploid cell
  • 3 cells move at the end of the embryo sac and later disintegrates
  • 3 cells move in the entry of embryo sac.

Question 33

Sexual Reproduction: 1st Step

Answer 33

Inside the anther’s pollen sacs, diploid cells divide by meiosis to produce four haploid microspores

Question 34

Sexual Reproduction: 2nd Step

Answer 34

Meanwhile, meiosis also occurs in the female flower parts. The diploid cell in megaspores initially produces 4 haploid cells. Three of these cells disintegrate leaving one large megaspore.

Question 35

Sexual Reproduction: 3rd Step

Answer 35

In the anther of the flower, each of the four haploid microspores develops and forms pollen grains. Each of these pollen grains contain one large and one small cell. The large cell becomes the pollen tube, and the small cell eventually forms two-sperm nuclei.

Question 36

Sexual Reproduction: 4th Step

Answer 36

In the embryo sac of the flower, the large haploid megaspore undergoes 3 mitotic divisions forming 8 cells. Eventually, 2 cells fuse together thus becoming one cell with two nucleus. Thus the result is a seven-celled structure.

Question 37

Sexual Reproduction: 5th Step

Answer 37

After a pollen grain lands on the stigma, a pollen tube emrges. When the pollen tube reaches an ovule, it discharges its two sperm nuclei into the embryo sac.

Question 38

Sexual Reproduction: 6th Step

Answer 38

One sperm fertilizes the egg cell and forms a diploid zygote which will later develop into an embryo.

Question 39

Sexual Reproduction: 7th Step

Answer 39

The other sperm nucleus fuses with the embryo sac central cell’s two nuclei. The result is a triploid cell that will become a tissue called endosperm

Question 40

Sexual Reproduction: 8th Step

Answer 40

Immediately after fertilization, the ovule contains an embryo sac with a diploid zygote and a triploid endosperm.

Question 41

Sexual Reproduction: 9th Step

Answer 41

The ovule eventually develops into a seed: a plant embryo together with its stored food, surrounded by a seed coat.

Question 42

Sexual Reproduction: 10th Step

Answer 42

The ovary grows rapidly to form the fruit.

Question 43

Fruit

Answer 43

• Protection of seeds

- Fruits promote seed dispersal

Question 44

Mechanisms of Seed Dispersal

Answer 44

To prosper, seeds must be widely dispersed. Plants use biotic dispersal agents as well as abiotic agents such as water and wind.