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Asexual Reproduction & Plant reproduction

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Presentation on theme: "Asexual Reproduction & Plant reproduction"— Presentation transcript:

1 Asexual Reproduction & Plant reproduction

2 Asexual & Sexual Reproduction
Sexual reproduction produces offspring that are genetically different from their parents. Asexual reproduction produces offspring genetically identical to their parent. Examples: Binary Fission Budding Spore Production Fragmentation Parthenogenesis

3 Modes of Reproduction Asexual Reproduction
One parent cell divides by mitosis to produce 2 identical cells that are clones of the parent

4 Types of Asexual Reproduction
Budding - an outgrowth on the parent organism that develops into a new organism that eventually separates from the parent. Example-yeast and hydra 

5 2. Binary fission –DNA is copied through mitosis, causing the original
2. Binary fission –DNA is copied through mitosis, causing the original parent cell to split into two smaller, genetically identical cells. Example-bacteria

6 3. Spore production - spores are produced by mitosis and are released from the original parent cell for dispersal. Example – Fungi (Rhizopus stolonifera)

7 4. Fragmentation – when a piece of the parent organism breaks off and is dispersed. Each section is able to form a new organism. Example - House plants formed from cuttings Planaria flatworm

8 5. Parthenogenesis – when offspring are produced from unfertilized eggs
Example - some insects, such as the Oleander aphid

9 Sexual Reproduction In sexual reproduction new individuals are produced by the fusion of haploid gametes to form a diploid zygote. Sexual reproduction offers the benefit of generating genetic variation among offspring, which enhances the chances of the population's survival.

10 Sexual Reproduction in Angiosperms

11 Parts of the flower Pistil: The ovule producing part of a flower. Stigma: the sticky surface at the top of the pistil; it traps and holds the pollen. Style: the tube-like structure that holds up the stigma. Ovary: where ovules are produced Ovule: The female gamete (i.e. Egg)

12 Stamen: The pollen producing part of a flower
Anther: The part of the stamen where pollen is produced. Filament: thread-like part that holds up the anther Pollen: the male gamete (i.e. sperm)

13 Fruit - the mature ovary
Seed - the mature ovule

14 Life Cycle of Flowering Plants
1. Pollination Pollen is transferred from the anther to the stigma Two types: Self-pollination: occurs within the same flower, or between flowers on the same plant Cross-pollination: Occurs between flowers on different plants

15 2. Fertilization 3. Seed Development
Pollen tube grows down through the style to deliver sperm nucleus to the egg Egg and sperm unite to form a zygote 3. Seed Development Zygote grows and develops into an embryo plant Ovule wall thickens to become a seed coat Seed also contains stored food for the developing embryo

16 4. Fruit Development Ovary tissue develops to enclose the seeds
This is called the fruit (ex: apple, tomato, green pepper Aids in seed dispersal

17 What is found in a pollen grain?
A generative nucleus which divides to produce two sperm nuclei A tube nucleus which causes the pollen tube to grow

18 What is found in an ovule?
The ovule contains: One Egg Two polar bodies

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20 What is double fertilization?
When the pollen tube enters an ovule: one sperm nucleus fuses with an egg to form the zygote (2n) the other combines with two polar nuclei to form the endosperm (3n) - a food reserve

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