Reproduction In plants

Question 1

Asexual reproduction

Answer 1

a process resulting in the production of genetically identical offspring from one parent

Question 2

Advantages and Disadvantages of Asexual reproduction

Answer 2

Adavantages:
-Only one parent is required: Helpful in organisms where finding a mate is difficult
-Can reproduce quickly: Large quantities of offsprings can be produced. Helps dominate a habitat and prevents competition form other species.
-Takes less energy to reproduce asexually
Disadvantages:
-Lack of diversity: all offsprings are genetically identical
-Prone to extinction: As offsprings are genetically identical, thus disease which harms one will harm all of the offsprings
-Cannot adapt: Cannot adapt to changes in the environment.
-Overpopulation: Too many offsprings may be produced, which causes Overpopulation

Question 3

Sexual reproduction

Answer 3

A Process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other

Question 4

Nuclei of gametes and nucleus of a zygote

Answer 4

nuclei of gametes are haploid and that the nucleus of a zygote is diploid

Question 5

Fertilisation

Answer 5

The fusion of gamete nuclei

Question 6

advantages and disadvantages of sexual reproduction

Answer 6

Advantages:
-Wide Diversity: each offspring is genetically unique
-Promotes survival: Each organism is unique so diseases cannot be spread as easily
-Organisms: can adapt: Each offspring born with different genes, Those with genetic advantages are likely to survive, those with genetic disadvantages are likely to die. Allows species to evolve through natural selection
Disadvantages:
-Two parents are required: May be difficult for some species to find mates, Can be difficult to find mates where species are endangered.
-Fewer offspring produced: Takes longer and requires more energy to produce offspring. Less efficient than asexual reproduction.

Question 7

Functions of:

Answer 7

• Sepal: Protects flower while it is a bud
• Petal: Brightly colored, to attract insect to the flower, Also attracted by scent and nectar in the plant.
• Anthers: Contain pollen grains, which contain male gametes
• Stigma: Catch pollen grains
• Ovaries: Contain ovules that contain female gametes

Question 8

anthers and stigmas of a wind-pollinated flower

Answer 8

• Anthers: The anthers dangle outside the flower, where they catch the wind
• Stigmas: Are large and feathery and dangle outside the flower, where the pollen in the air may land on it.

Question 9

pollen grains of insect-pollinated and wind-pollinated flowers

Answer 9

Insect-pollinated:
-Sticky or sticky pollen grains, which stick to insects
Wind-pollinated:
-Smooth, light pollen which can be blown in the wind.

Question 10

Pollination

Answer 10

the transfer of pollen grains from the anther to the stigma

Question 11

Self-pollination

Answer 11

the transfer of pollen grains from the anther of a flower to the stigma of the same flower or different flower on the same plant

Question 12

Cross-pollination

Answer 12

transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species, Can only occur if plants are open.

Question 13

How fertilisation occurs

Answer 13

fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule.

1. Pollen grain lands on a plant stigma
2. If pollen of the same species, a pollen tube begins to grow
3. Pollen moves down pollen tube to the ovule
4. Fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule, Forming a zygote
5. Zygote develops into an embryo plant

Question 14

structural adaptations of insect-pollinated and wind-pollinated flowers

Answer 14

Insect-pollinated:
-Sticky or sticky pollen grains, which stick to insects
-Often strongly scented
-Anther inside the flower
-Stigma inside the flower
Wind-pollinated:
-stigmas of wind-pollinated plants are long, feathery and hang outside the flowers. They are well adapted to catching pollen
-Anther dangle out of the flower

Question 15

the growth of the pollen tube and its entry into the ovule followed by fertilisation

Answer 15

1. If pollen of the same species, a pollen tube begins to grow
2. Pollen moves down pollen tube to the ovule
3. Fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule, Forming a zygote
4. Zygote develops into an embryo plant

Question 16

Environmental conditions that affect germination of seeds

Answer 16

• Water: Water moves into the seed causing it to swell, allows embryo to begin growing
• Oxygen: Used in respiration to produce energy for growth
• Temperature: Seed contains enzymes, For respiration, it will work faster with the plants optimum temperature. Hence why seeds are dormant in winter and grow again in spring, due to the temperature.