Presentation on theme: "Reproduction in Flowering Plants Objective: 1.Describe the reproductive organs of the plant 2.Explain the process of sexual reproduction in angiosperms."— Presentation transcript:
Reproduction in Flowering Plants Objective: 1.Describe the reproductive organs of the plant 2.Explain the process of sexual reproduction in angiosperms 3.Describe the structure and function and structure of seeds Homework: Learn about and describe different methods of seed dispersal
Quiz 1.Why are the palisade and the spongy mesophyll called the working layers of the leaf? 2.What is cambium and what does it do? 3.How does the arrangement of the stomata leading into the spongy mesophyll (filled with air spaces) ensure chlorophyll containing cells have a constant supply of carbon dioxide for photosynthesis? 4.On board
Parts of a flower 9Ad
Sexual Reproduction in Angiosperms Plants reproduce sexually The products of this sexual reproduction are seeds. These seeds are contained inside an ovary. Which develops into a fruit.
Reproductive Parts Male reproductive organs (stamen): Anther: produces pollen grains Filament: supports anther above female reproductive organs Female reproductive organs (carpel): Stigma: sticky landing site for pollen grains Style: tube that leads down to ovary Ovary: contains ovules that develop into seeds
Reproductive Mechanisms Pollen (male gamete) from one plant lands 9Ad stigma pollen on the stigma of another plant. This is called pollination.
Methods of Pollination Natural Reproduction Pollination in angiosperms can happen by wind or animals. Animals can transfer pollen (bees) from one plant to the other. –They are called pollinators Pollen can be blown from one plant to another. –Wind dispersal
size Selective breeding in plants colour taste texture Selective breeding and cross-breeding are carried out on plants to produce flowers and crops with desirable characteristics… 9Ad
9A Plant-breeding techniques Anne the plant breeder chooses two parent plants with useful characteristics. One plant will be the female parent. Anne removes the anthers and covers the flower with a bag. Why? She puts the bag over the flower again. Later she collects the seeds and grows them to produce the new plant. female parent anthers removed collected pollen The other plant is the male parent. Its anthers develop as normal. Anne collects its pollen and brushes it onto the female plant.
9Ad From Pollen to Ovary The pollen grain grows a pollen tube pollen tube ovary containing ovule towards the ovary, which contains the ovule and egg cell (female gamete).
Fertilisation takes place when the sperm nucleus from the pollen grain enters the egg cell. The resulting zygote eventually turns into a seed. Fertilization 9Ad pollen tube with pollen grain nucleus ovule Embryo grows inside the ovule. egg cell
Compare With your neighbour, discuss how the reproductive system in plants is similar to the reproductive system in humans.
Quiz 1.Name three different methods of seed dispersal. 2.Chose one method and explain how it effectively disperses seeds away from plant. 3.What are the male parts of the plant called? 4.What is it called when pollen from one plant lands on the stigma of another plant.
Comparing Plant and Human Reproductive Systems Plant Male and Female organs Male Gamete is pollen Female Gamete is egg produced in ovule Pollen nuclei fuses with egg nuclei (fertiliation) Diploid zygote Zygote grows into embryo Embryo grows inside protective seed coat Cotyledons provide nourishment Human Male or Female organs Male Gamete is sperm Female Gamete is egg produced in ovary Sperm nuclei fuses with egg nuclei (fertilization) Diploid zygote Zygote grows into embryo Embryo grows inside protective womb Placenta provides nourishment
Zygote to Embryo The zygote will grow through the process of mitosis to form an embryo (The ovule is now called a seed and is covered by a protective seed coat.) seed coat food supply (cotyledon) embryo seed
Fruit Formation Some plants produce fruit containing seeds. Fruit: Mature ovary Tissue surrounding the embryo develops into fruit. When the fruit is fully developed it drops off the plant, or is carried away by an animal. When fruit decomposes it releases the seed and germination can occur.
Germination A seed requires moisture (water) to germinate. The as the embryo grows, the root and shoot break through the seed coat. Nutrients stored in the cotyledon provide nourishment and support early development
Life cycle of an angiosperm
Plenary.. 1.What is the function of the flower? 2.What is a seed? 3.What basic condition is required for a seed to germinate? 4.Describe two methods of pollination.