Lesson planScience

Class 10th

Topic: Reproduction In OrganismsSub- Asexual Reproduction In Organisms

GENERAL OBJECTIVES

• To develop scientific awareness among the students about reproduction in living things

• To aware the students about different parts of organisms related to reproduction.

• Types of reproduction.• To develop the inter disciplinary approach

for study in different subjects.• To make the students confident and

present topic in class.• To make students aware about their

surroundings & environment.

SPECIFIC OBJECTIVES

To enable the students to know about asexual reproduction in organism

To know different modes of asexual reproduction

To get the students aware about different parts of a plant which take part in asexual reproduction

PREVIOUS KNOWLEDGE TESTING

• See this picture and tell about this • Parents and children• How the continuation of race takes

place?• By Reproduction.

• WHAT IS REPRODUCTION?• Reproduction is the process of formation of new individuals of

its own kind.

• WHY IS IT IMPORTANT?• Reproduction is important for the continuation of the race.

• WHAT ARE ITS DIFFERENT TYPES ?• Two types.• What are these?

Sexual Reproduction

AsexualReproduction

Reproduction

Do you know what is Asexual Reproduction?

Well students today we will discuss about Asexual Reproduction in organisms

PresentationAsexual Reproduction

Asexual reproduction is the formation of new individuals from single parent (monoparental)

New individuals are similar to the parents. morphologically & genetically similar

organisms known as clone.

How many types of Asexual Reproduction is?

Types of Asexual Reproduction

Fission

Fragmentation

RegenerationBudding

Vegetative Propagation

Spore formation

What do you means by fission?

• Fission means to break down of individual into two equal parts.

What are the name of these?• These are • 1 Binary Fission• 2 Multiple Fission

(A)Fission

Binary FissionFavorable condition. eg. Protoza (amoeba).

Multiple Fissionunfavorable condition. eg. Amoeba , Plasmodium.

What are favorable conditions

1.Binary Fission Can you give any example of binary fission?• Yes, Amoeba

• See the pictures and tell how many Amoebas are produced

• Two

• Amoebas reproduce (make more amoebas) by a process called binary fission.• This means that one amoeba can

split in half and make two identical new amoebas.• In this process mitotic nuclear

division followed by cytoplasmic division

(2) Multiple Fission

What is multiple fission?• Formation of more than two individuals

under unfavorable conditions .Can you give an example?• Yes , Amoeba and Plasmodium

Can you describe this picture?

amoebaCyst formation

Division of nucleus

Daughter cells formation New pseudopodispore or amoebas

Fragmentation in Spirogyra

What is the name of this fission?

(B) Fragmentation

• In multicellular organisms i.e. simple body organization .body breaks up into two or more parts .

• But it is not true in all multi cellular organisms

• i.e. specialized cell are organized and placed at specific position in the body.

Do you know what these pictures represent?

These pictures show an out growth like structure

Budding In Hydra

Budding- an individual grows out of the body of the parent.

Hydra Budding

New organism

Cactus Budding

(C) Budding

• Budding- an individual grows out of the body of the parent. • Hydra use regenerative cells for

reproduction in the process of budding • Outgrowth or Budding is due to

repeated division of cells.

Observe the surface of potato-A- ………..?B- ………..?

How potato reproduces ?Ans :- By vegetative propagation.How many types of vegetative

propagation in plants?Ans :- By roots, stem and leaves.

Potato

Vegetative reproduction by RootsSome plants use their roots for asexual

reproduction. Example: DahliaIn dahlia each root tuber can form a whole new

plant.

Vegetative reproduction by Leaves

• This photo shows the leaves of the common ornamental plant Bryophyllum (also called Kalanchoë).

• Leaf margins produce tiny plantlets that fall off and can take up an independent existence.

Can plants reproduce by artificial Vegetative propagation?

Ans:-yes

What is Artificial Vegetative propagation

Ans:- Propagation by stem cutting and grafting

Artificial Vegetative propagation

Artificial methods used in agriculture & horticulture to propagate / grow new plants that are identical to the parent

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Grafting• Involves fixing /

binding together the cut surfaces of 2 plants (similar) so they grow as one.

• Useful qualities from both plants combined into one e.g. rose flower and thorn-less stem e.g. apple trees. 29

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Layering

• A branch of a plant is bent over and pinned down into the soil at a node.

• It is covered over with soil & eventually new roots & shoots develop.

• Useful for the propagation of woody plants e.g. blackberry, gooseberry.

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What is regeneration?Ans:-formation of new individual.

(E)Regeneration

• Ability to give rise to new individual organisms from their body parts.

eg. Hydra Planaria.

(F) Spore FormationUnicellular or multicellular, reproductive or distributional cells developing into a number of different phases of the complex life cycles of the fungi

Latest technology for propagation of plants in laboratory (Micro- propagation)

• Some cells are removed from plant are placed in a dish with nutrients & growth regulators

• They grow into a group of similar cells called a callus

• Which develops into a small plant & then placed into compost.

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(Tissue Culture)

Group Formation

Whole class will be divided into four groups:

Group No. 1 will be given different plants and show its different parts.

Group No. 2. will be asked to identify the plants which reproduce asexually with stem.

Group No. 3. will be asked to identify the plants which reproduce asexually with roots

Group No. 4. will collect the plants which reproduce through the leaves.

Comment on this crop

Activities• Collect water from the lake or pond that appear

dark green and contain filamentous structures. Observe it under microscope in school lab.

• Students will be asked to collect & identify the Organisms which reproduce asexually.

Evaluation What is reproduction ?

Define asexual reproduction ?

Name the parts of a plant by which it can reproduce asexually.

Which part of the potato plant we eat?

Sheela has gone to a garden. She collected roots of Dahlia over there. She said that plant can not reproduce through these roots. Are you agree. Explain?

Home Assignments

• Can you think of reason why more complex organisms can not give rise to new individuals through regeneration.

• Why asexual reproduction is not so common in higher animals?

Home assignment

• Make collection of plants which reproduce through stem in your locality.

• Make list of plants whose roots are used in your kitchen as vegetable.

• List the ornamental plants which reproduce by artificial vegetative propagation in your locality.

Exercise to develop research attitude among the students

• Students will be asked to visit A garden/ Nursery/ Polyhouse/ Tissue culture lab and prepare a complete Project report related to asexual reproduction.

• At the end of vacation they have to present their project report in the class.

THANK YOU