Lecture 7: Flowers, Pollinators and Reproduction

Question 1

What is a zygomorphic flower?

Answer 1

The flower can be divided into two equal parts or mirror images, by one line or plane of symmetry, bilaterally symmetrical

Question 2

What is an example of a zygomorphic flower?

Answer 2

Orchid

Question 3

What is an actinomorphic flower?

Answer 3

The flower can be divided into two equal parts or mirror images by multiple lines or planes of symmetry; radially symmetrical

Question 4

What is a perfect flower?

Answer 4

Flower that contains both stamens and pistils

Question 5

What is an imperfect flower?

Answer 5

Flower that contains stamens or pistils but not both

Question 6

What is a complete flower?

Answer 6

Has sepals, petals, stamens and pistils

Question 7

What is an incomplete flower?

Answer 7

Missing one or more of the four main parts

Question 8

What is a monoecious species?

Answer 8

One household where male and female flowers (unisexual) are found on the same plant

Question 9

What is a dioecious species?

Answer 9

Two households where male and female flowers are found on separate plants

Question 10

What is pollination?

Answer 10

Transfer of pollen from the anther to the stigma

Question 11

What are the two things required in pollination?

Answer 11

Flowers (which provide pollen and stigmas)

Pollination vectors (wind, water, animals, etc.)

Question 12

What is wind pollination in grasses?

Answer 12

Grass produces pollen and the flowers are designed to catch pollen in the wind with long feathery stigmas.

Grass flowers that produce pollen are found high on the plant so that they are exposed to the wind and allow for pollen dispersal

Question 13

What are the steps of wind pollination in grasses?

Answer 13

Pollen grains are dry preventing them from sticking to one another

Male flowers are located at the top of the plant which allows the wind to disperse the pollen

The anthers make large quantities of pollen

Filaments of the stamens move in the wind shaking the pollen out of the anthers

Female flowers are located lower on the plant with large feathery and sticky stigmas to catch the falling pollen

Question 14

What is animal pollination?

Answer 14

Plant and animals benefit from this relationship. Plant gets pollinated, animal gets nutrients

Question 15

How do flowers attract animal pollinators?

Answer 15

Scent, colour(s), shape

Question 16

How do bees pollinate?

Answer 16

Collect pollen in their scopae which are sense electrostatic hairs found on back legs or bottom of the abdomen.

OR

Collen pollen and nectar through pollen baskets (specialized scopae found on honey and bumblebees)

Question 17

What are the two types of pollination?

Answer 17

Self pollination and cross pollination

Question 18

What is self pollination?

Answer 18

Flowers on the same plant contain the same genetic material

Flowers on different plants of the same clone ALSO contain the same genetic material (considered self pollination)

Question 19

What are the advantages of self pollination?

Answer 19

Purity of the race is maintained
Less wastage of pollen grains
Less dependence on external factors for pollination

Question 20

What are the disadvantages of self pollination?

Answer 20

Cannot produce new varieties
Vigor of the species may be reduced
Offspring may be more susceptible to disease

Question 21

What is cross pollination?

Answer 21

Involves transfer of pollen from plant to another plant that is not the same clone

Two plants made of different genetic material

Mixing of genetic material when cross pollination and fertilisation occurs

Question 22

What are the advantages of cross pollination?

Answer 22

The introduction of new genes is beneficial to the species (new varieties)

The resulting seeds and plants have improved vigor and vitality

New plants tend to have improved resistance to disease

Question 23

What are the disadvantages of cross pollination?

Answer 23

More wastage of pollen grains

Pollination may not occur due to distance between plants

Possible introduction of detrimental characteristics

Great dependence on external factors for pollination

Greater energy spent by some plants to produce flowers to attract animal pollinator

Question 24

What is sexual reproduction?

Answer 24

Procedure involved to produce a new organism by combining genetic material of two different cells ensuring the survival of the species

Question 25

What are the steps of sexual reproduction in plants?

Answer 25

Pollen grain lands on the stigma of a compatible flower

Pollen grain consists of two cells (one cell produces a pollen tube)

Pollen tube grows through the style and towards the opening of one of the ovules in the ovary

The second cell divides to form two sperm cells that travel down the pollen tube

The two sperm cells are released into the ovule

One of the sperm cells fuses with the egg cells in the ovule to form the zygote, a fertilised egg

The other sperm cell fuses with another cell in the ovule to produce the endosperm which provides food for the zygote

Zygote divides and grows into an embryo

Ovule grows and becomes a mature seed

Ovule grows and becomes a seed

Ovary grows and becomes a fruit containing seeds

Seed is then dispersed

Question 26

How do seeds travel?

Answer 26

Wind
Animals
Water
Bursting/exploding
Humans

Question 27

Explain the characteristics and strategies that wind-pollinated plants have developed to increase
the chances of pollination taking place

Answer 27

Wind-pollinated plants spend their energy on producing as much pollen as possible. They do not waste any of their energy on beautiful/colorful petals/sepals/etc, or scent.

Next, the stamens are located in the feathery plumes to make it easier for the wind to pick up pollen. The stigmas are located on the lower side of the plant to make it easier to catch pollen when the wind blows. They also have dry pollen which prevents them from sticking together.

Lastly, wind-pollinated plants are planted very close to each other to increase the chance that the right direction of the wind will result in the pollination of all nearby plants.

Question 28

Explain some of the general characteristics and strategies that plants pollinated by insects and
other animals have developed to increase the chances of pollination taking place

Answer 28

Mutualistic relationship where both species benefit. Plant produces something that insects/animals want to eat. Animals/insects eat it, and carry the pollen with them elsewhere.