write 15 notes on the chapter Reproduction in plants
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Chapter Notes 2 - Chapter 12: Reproduction in Plants, Class 7, Science
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Reproduction In Plants - Notes
Reproduction: The process by which a living being produces its offspring is called reproduction.
Types of Reproduction:
1 - Asexual Reproduction: When a single parent is involved in the process, it is called asexual reproduction. Following means of asexual reproduction are used by plants:
(a) Budding: This method is used by unicellular plants; like yeast. Yeast is a fungus and fungi are also known as non-green plants. The yeast cell produces a bud which gets its own nucleus. The bud develops to certain size and detaches from the mother cell to produce the new yeast.
Seven Science Reproduction in Plnats, budding in yeast
(b)Fragmentation: In some simple plants, the plant body is divided into smaller fragments. Each fragment then develops into a new plant. Example: Spirogyra.
Seven Science Reproduction in Plants Fragmentation in Spirogyra cbse ncert
(c) Spore Formation: Special spore-bearing organs are present in some plants; especially in fungi and algae. These are called sporangiophores. The sporangiophore bears spores. The spores germinate to develop a new plant.
Seven Science Reproduction in Plants Spore formation in fungi
(d) Vegetative Propagation: When a new plant is developed by a vegetative part; such as root, stem or leaf; it is known as vegetative propagation. For example: when the tuber of potato is cut into several pieces and each piece bears an ‘eye’; each piece produces a new plant. The stems of moneyplant, rose, mango, etc. can produce new plants when they are inserted in soil. The leaf of bryophyllum produces new plants through its notches.
Review Questions:
Q(A) Give an example of an organism which reproduces by budding.
Answer: Yeast
Q(B)How many parents are involved in asexual reproduction?
Answer: Only one
2.) Sexual Reproduction: When two parents are involved in the process, it is called sexual reproduction. Two gametes, viz. male and female gametes, are formed. The fusion of male and female gametes is called fertilization. Zygote is formed after fertilization. The zygote develops into an embryo and finally into a new individual.
Seven Science Reproduction in Plants Structure of Flower Sexual Reproduction cbse ncert
Flower: Flower is a special organ of flowering plants (angiosperms) which works as the reproductive system. A flower is composed of four distinct whorls.
(1) The outermost whorl is called calyx. It is composed of green leaf-like structures; called sepals.
(2) The second whorl is called corolla. It is composed of colourful structures; called petals. Petals are colourful so that insects and other animals can be attracted towards them. This is necessary for pollination.
(3) Androecium: The third whorl is called androecium. It is composed of stamens. Stamen has two main parts. The tube-like portion is called filament. The capsule like structure at the top is called anther. The anther produces pollen grains; which are the male gametes.
(4) Gynoecium: The whorl at the center is called gynoecium. It has a swollen base; called ovary and a tube-like structure; called style. The top of the tube is somewhat flattened and is called stigma. Ovary produces the eggs or female gametes.
Review Questions
QA -What is the benefit of colourful petals for plants?
Answer: Colourful petals attract insects, birds and other animals. It helps in cross pollination.
QB - What is the name of the male gamete in a flowering plant?
Answer: Pollen grain
Pollination: The transfer of pollen grains from anthers to stigma is called pollination. Pollination is of two types, viz. self pollination and cross pollination.
Self Pollination: When anthers of the same flower are transferred to the stigma; it is called self pollination.
Cross Pollination: When anthers from a different flower are transferred to the stigma; it is called cross pollination. The flowers can be on the same plant or on different plants. Cross pollination is the norm in most of the plants. Plants need help from various agents of pollination to carry out cross pollination. Wind, insects, birds and other animals play the role of agent of pollination.
Seven Science Reproduction in Plants Fertilisation cbse ncert
Fertilization: The fusion of the male gamete and the female gamete is called fertilization. When pollen settles on top of the stigma, it germinates to produce a pollen tube. The pollen tube enters the ovary through the style. Male nuclei are transferred to the ovary, through the pollen tube. The cell formed, just after fertilization, is called zygote. Zygote develops into embryo. Each embryo develops into a seed. The seed is an embryo which is enclosed in a protective coat. The ovary gets transformed into fruit.
Full Screen
Reproduction In Plants - Notes
Reproduction: The process by which a living being produces its offspring is called reproduction.
Types of Reproduction:
1 - Asexual Reproduction: When a single parent is involved in the process, it is called asexual reproduction. Following means of asexual reproduction are used by plants:
(a) Budding: This method is used by unicellular plants; like yeast. Yeast is a fungus and fungi are also known as non-green plants. The yeast cell produces a bud which gets its own nucleus. The bud develops to certain size and detaches from the mother cell to produce the new yeast.
Seven Science Reproduction in Plnats, budding in yeast
(b)Fragmentation: In some simple plants, the plant body is divided into smaller fragments. Each fragment then develops into a new plant. Example: Spirogyra.
Seven Science Reproduction in Plants Fragmentation in Spirogyra cbse ncert
(c) Spore Formation: Special spore-bearing organs are present in some plants; especially in fungi and algae. These are called sporangiophores. The sporangiophore bears spores. The spores germinate to develop a new plant.
Seven Science Reproduction in Plants Spore formation in fungi
(d) Vegetative Propagation: When a new plant is developed by a vegetative part; such as root, stem or leaf; it is known as vegetative propagation. For example: when the tuber of potato is cut into several pieces and each piece bears an ‘eye’; each piece produces a new plant. The stems of moneyplant, rose, mango, etc. can produce new plants when they are inserted in soil. The leaf of bryophyllum produces new plants through its notches.
Review Questions:
Q(A) Give an example of an organism which reproduces by budding.
Answer: Yeast
Q(B)How many parents are involved in asexual reproduction?
Answer: Only one
2.) Sexual Reproduction: When two parents are involved in the process, it is called sexual reproduction. Two gametes, viz. male and female gametes, are formed. The fusion of male and female gametes is called fertilization. Zygote is formed after fertilization. The zygote develops into an embryo and finally into a new individual.
Seven Science Reproduction in Plants Structure of Flower Sexual Reproduction cbse ncert
Flower: Flower is a special organ of flowering plants (angiosperms) which works as the reproductive system. A flower is composed of four distinct whorls.
(1) The outermost whorl is called calyx. It is composed of green leaf-like structures; called sepals.
(2) The second whorl is called corolla. It is composed of colourful structures; called petals. Petals are colourful so that insects and other animals can be attracted towards them. This is necessary for pollination.
(3) Androecium: The third whorl is called androecium. It is composed of stamens. Stamen has two main parts. The tube-like portion is called filament. The capsule like structure at the top is called anther. The anther produces pollen grains; which are the male gametes.
(4) Gynoecium: The whorl at the center is called gynoecium. It has a swollen base; called ovary and a tube-like structure; called style. The top of the tube is somewhat flattened and is called stigma. Ovary produces the eggs or female gametes.
Review Questions
QA -What is the benefit of colourful petals for plants?
Answer: Colourful petals attract insects, birds and other animals. It helps in cross pollination.
QB - What is the name of the male gamete in a flowering plant?
Answer: Pollen grain
Pollination: The transfer of pollen grains from anthers to stigma is called pollination. Pollination is of two types, viz. self pollination and cross pollination.
Self Pollination: When anthers of the same flower are transferred to the stigma; it is called self pollination.
Cross Pollination: When anthers from a different flower are transferred to the stigma; it is called cross pollination. The flowers can be on the same plant or on different plants. Cross pollination is the norm in most of the plants. Plants need help from various agents of pollination to carry out cross pollination. Wind, insects, birds and other animals play the role of agent of pollination.
Seven Science Reproduction in Plants Fertilisation cbse ncert
Fertilization: The fusion of the male gamete and the female gamete is called fertilization. When pollen settles on top of the stigma, it germinates to produce a pollen tube. The pollen tube enters the ovary through the style. Male nuclei are transferred to the ovary, through the pollen tube. The cell formed, just after fertilization, is called zygote. Zygote develops into embryo. Each embryo develops into a seed. The seed is an embryo which is enclosed in a protective coat. The ovary gets transformed into fruit.
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