Lecture 3- Flowering Plants

Question 1

The invention of the _____ gives rise to angiosperms

Answer 1

flower

Question 2

Flowering plants

Answer 2

-division anthophyta
+250,000 species
Reproductive organs in flowers
both male and female: bisexual or cosexual
Vascular plants, therefore sporophyte dominant
Heterosporous
Microgametophyte= pollen
Megagametophyte= 8 nuclei
Triploid (3n) endosperm
-Bagged lunch for embryo in seed is new tissue called endosperm
-Endosperm: triploid, three chromosome sets

Question 3

Structure of a flower

Answer 3

4 whorls
1) Sepal: base of flower
2) Petals: attract pollinators
3) Stamen: consists of the anther and filament. produces microspores
filament- stalk that anther sits on
anther- has two sporangium, where meiosis and pollen is
4) Carpel: consists of stigma, style, and ovary
stigma:tip of carpel that receives pollen
style: connects stigma to ovary
ovary: contains one or more ovules
-develops into fruit

Question 4

Androecium

Answer 4

all male structures of flower

Question 5

gynoecium

Answer 5

all female structures of flower

Question 6

Pollination

Answer 6

when pollen lands on stigma

Question 7

Fertilization

Answer 7

when pollen grows down the style and fertilizes ovule

Question 8

Monocot

Answer 8

• one cotyledon
• parallel veins
• scattered vascular tissue
• fibrous roots, no main root
• pollen grain with one opening
• organs in multiples of 3

Question 9

Eudicot

Answer 9

• two cotyledon
• vascular tissue ring like
• net like veins
• one main root called tap root
• pollen grain opening with 3 holes
• organs in multiples of 4-5

Question 10

pollination

Answer 10

Definition: The arrival of pollen on the stigma (flowering plants) or on receptive female cone (conifers)
Only occurs in seed plants

Question 11

Types of pollination

Answer 11

insects, birds, bats, wind

Question 12

Reward for pollinator

Answer 12

nectar pollen

Question 13

Advertisement for plant

Answer 13

• showy flower

- odour

Question 14

Pollination syndrome

Answer 14

• set of floral traits associated with specific pollinator groups
• convergent evolution

Question 15

Bee syndrome

Answer 15

• various shapes: specialized or nah
• any colour but red
• odour: specialized or none

Question 16

Bat/moth syndrome

Answer 16

• tubular in shape, open at night
• white and yellow
• sweet odour at night
• large quantity nectar

Question 17

Bird syndrome

Answer 17

• tubular in shape
• red and yellow
• no odur
• weak nectar

Question 18

Wind syndrome

Answer 18

• not attractive or specialized
• no colour
• no odour
• no nectar
• large quantities pollen

Question 19

Deceit pollination

Answer 19

• plants gives no reward to pollinator
• seen in orchids
• bees come in, mess around, gets pollen on its self, goes to other plants and fertilizes

Question 20

Angiosperm Life cycle

Answer 20

In the megasporangium of each ovule, the megasporocyte divides by meiosis, producing four megaspores. One survives and gives rise to a female gametophyte.
(In conifers: the megaspores divides many times to get a megagametophyte that’s thousands cells big). In flowering plants, megaspore divides 3 times to make 8 cells.
Female gametophyte is 8 nuclei and 7 cells big because female gametophyte has middle cell called central cell that has 2 of the nuclei in it called POLAR NUCLEI
That central cell is a NOVEL feature in plants. Unique to flowering plants, is going to be fertilized

POLAR NUCLEI MAKE UP THE CENTRAL CELL

On the anther, each microsporangium contains microsporocytes that divide by meiosis, producing 4 microspores that develop into pollen grains. Pollen grain of flowering plant is different from that of a conifer in that it has 2 active sperm cells
-2 active sperm cells, conifers have 1

5. Pollen growns down style to meet ovule
   One sperm fertilizes egg nucleus and becomes zygote, other sperm fertilizes central cell and becomes brand new tissue called endosperm.
   Endosperm: triploid because it has 2 haploid chromosome sets from mom, 1 chromosome set from dad
   2 genetically identical to egg, 1 genetically identical to sperm that fertilized egg

Question 21

Double fertilization

Answer 21

Angiosperms have double fertilization
One sperm fertilizes the egg
Embryo (2n= diploid)
 One sperm fertilizes the two polar nuclei of the central cell
Endosperm (3n= triploid)
Sperm have no cell wall, simply nuclei

Question 22

Ovaries

Answer 22

become fruit

Question 23

Ovules

Answer 23

become seeds

Question 24

fruit

Answer 24

has atlas one seed

-protective covering