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12B01

Reproduction In Organisms

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12B01 Reproduction In Organisms

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Learning Objectives

Introduction To Reproduction

Asexual Reproduction

Sexual Reproduction

12B01 Reproduction In Organisms

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12B01.1

Introduction To Reproduction

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What is reproduction ?

Parent

Offspring

12B01.1 Introduction To Reproduction

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Digestive System

Respiratory System

Circulatory System

12B01.1 Introduction To Reproduction

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Why is reproduction necessary ?

12B01.1 Introduction To Reproduction

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Got extinct

Dodo Bird

Tiger

At verge of extinction

Reproduction enables survival of the species

12B01.1 Introduction To Reproduction

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12B01.1

CV 1

Types of Reproduction

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Reproduction

Asexual

Sexual

12B01.1 Types Of Reproduction

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Asexual Reproduction

(Single parent involved)

Single Parent

Divides

Daughter Cells

12B01.1 Types Of Reproduction

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Asexual Reproduction

(Single parent involved)

Parent Amoeba

Nucleus divides

Cytoplasm divides

Two daughter Amoebae

For example, Amoeba

12B01.1 Types Of Reproduction

Two Daughter Amoeba

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Sexual Reproduction

(Two parents involved)

Male and Female

Parents

Gamete Production

Zygote

Fusion

Child

Sperm

Egg

12B01.1 Types Of Reproduction

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Concept Test

Ready for a Challenge

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Q. Asexual Reproduction involves :

A) Two Parents

B) One Parent

C) Three Parents

D) None of the above

Sol. B) One Parent

Explanation: In asexual reproduction, a single parent is capable of giving rise

to offspring while sexual reproduction requires two parents.

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(Time Duration : 02 Minutes)

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12B01.1

CV 2

Life Span and Phases of Life

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Life Span:

Plant Dies

Plant Grows

Seed Germinates

Plant Flowers

Flower Produces Fruit

Fruit Releases Seeds

Time period from birth to natural death of an organism

12B01.1 Introduction To Reproduction

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Av. 50-70 years

Av. 100-150 years

Av. 5-7 years

Av. 1-2 weeks

Life Span Of Different Organisms

12B01.1 Introduction To Reproduction

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Phases of Life:

Juvenile Phase

Ageing And Senescence

Death

Vegetative Phase

12B01.1 Introduction To Reproduction

Reproductive or Maturity Phase

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Annual

Biennial

Perennial

12B01.1 Introduction To Reproduction

Plants

All life phases well defined

Not clearly defined

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Bamboo

Strobilanthus kunthiana

(Neelakuranji)

12B01.1 Introduction To Reproduction

Flower once in their lifetime, generally after 50-100 years

Flowers once in 12 years

Did You Know?

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Concept Test

Ready for a Challenge

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Q. Life span is :

A) Time period from birth to natural death of an individual

B) Time period from birth to death of an individual

C) Time period from birth to maturity phase

D) None of the above

Sol. A)

Explanation: Time period from birth to maturity phase is termed as juvenile

phase

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Summary/Note making

Reproduction is the process in which an organism gives rise to offspring similar to itself.
Importance of reproduction is that it enables the continuity of species.
Based on whether there is participation of one organism or two, Reproduction is of two types : asexual & sexual reproduction.
Life span is the period from birth to natural death of an organism.
Three phases of life include juvenile phase, reproductive or maturity phase, ageing and senescence . This is followed by death.
Juvenile phase in plants is termed vegetative phase.

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Reference Questions

NCERT: 1, 8

Workbook: 3, 4

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12B01.2

Asexual Reproduction

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Recall Test

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Q1. Sexual Reproduction Involves:

A) One Parent

B) Two Parents

C) Three Parents

D) None of the above

Q2. All are true about Sexual Reproduction except:

A) Involvement of two parents

B) Formation of male and female

gamete

C) Fusion of male and female

gamete

D) Formation of only male gamete

Q3. Juvenile phase in plants is called

C) Vegetative phase

A) Maturity phase

B) Senescence

D) None of the above

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Q4. Maturity phase ends into :

A) Juvenile phase

B) Vegetative phase

C) Senescent phase

D) Any of the above

Q5. Identify the wrong statement :

A) Types of reproduction include asexual and sexual reproduction

B) Gametogenesis is the formation of gametes

C) Fusion of gametes takes place in asexual reproduction

D) Fusion of gametes takes place in sexual reproduction

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Sol.1 B)

Sol.2 D)

Sol.3 C)

Sol.4 C)

Sol.5 C)

Answers

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12B01.2

CV 1

Clone and Types of Asexual Reproduction

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Clone: Genetically and Morphologically similar individuals

12B01.2 Asexual Reproduction

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Clone:

Parent Cell

Daughter cells identical to each other and to the parent

Divides

Produced by asexual reproduction

12B01.2 Asexual Reproduction

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Types of Asexual Reproduction

Parent Amoeba

Nucleus Divides

Cytoplasm Divides

Two Daughter amoeba

Binary Fission In Amoeba

12B01.2 Asexual Reproduction

Cytoplasm Divides

Two daughter Amoeba

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Types of Asexual Reproduction

Multiple Fission In Amoeba

Parent Amoeba

Psuedopodiospores

Sporulation

Cyst

12B01.2 Asexual Reproduction

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Types of Asexual Reproduction

Budding In Yeast

Parent cell

Outgrowth

12B01.2 Asexual Reproduction

Bud

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Types of Asexual Reproduction

Fragmentation in Hydra

Parent

Fragments

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Buds in Hydra

Gemmules In Sponges

Zoospores of Chlamydomonas

Conidia of Penicillium

Zoospore

Conida

Bud

Mouth

12B01.2 Asexual Reproduction

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Concept Test

Ready for a Challenge

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Sol. A)

Explanation: In binary fission nuclear division precedes cytoplasmic division.

Q. In binary fission :

A) Nucleus divides first

B) Cytoplasm divides first

C) Nucleus and cytoplasm divide simultaneously

D) None of the above

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12B01.2

CV 2

Vegetative Propagation

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Internode

Node

Vegetative Propagation:

Daughter plant

Runner

Rhizome of ginger

Parent plant

Runner of strawberry plant

12B01.2 Asexual Reproduction

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Vegetative Propagation:

Offset of water hyacinth

Parent Banana Tree

Sucker

Offset

Sucker of banana plant

12B01.2 Asexual Reproduction

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Old Potato Tuber Planted In Soil

Bulb

Tuber

Eyes

New Potato Plant Growing From Bud

Bud

Main Bud

Fleshy Leaves

Leaf

12B01.2 Asexual Reproduction

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Leaf Buds Of Bryophyllum

Vegetative Propagules ?

Adventitious Buds

Units of vegetative propagation such as rhizome, runner, sucker, tuber, offset, bulb which are capable of giving rise to new offspring.

12B01.2 Asexual Reproduction

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Terror Of Bengal ?

Water hyacinth

Dead fishes

Water hyacinth grows at phenomenal rate by vegetative propagation, draining oxygen from water leading to death of fishes

12B01.2 Asexual Reproduction

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Concept Test

Ready for a Challenge

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Q. In Binary Fission :

A) Parent cell divides into four daughter cells

B) Parent cell divides into one daughter cells

C) Parent cell divides into two daughter cells

D) None of the above

Pause the Video

(Time Duration : 02 Minutes)

Sol. C)

Explanation: In binary fission the parent cell divides into two halves and each

rapidly grows into an adult (e.g., Amoeba, Paramecium) �

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Reference Questions

NCERT : 3, 6, 7

Workbook : 9

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In asexual reproduction, a single individual is capable of producing offspring.
Morphologically and genetically identical individuals are termed clones.
Binary fission involves division of parent cell into two halves and each rapidly grows into adult (e.g. Amoeba, Paramecium).
During unfavourable conditions Amoeba shows encystation. On return of favourable conditions encysted Amoeba divides by multiple fission producing. psuedopodiospores. Later sporulation takes place.
In fragmentation, body of the organism breaks into distinct fragments, each fragment grows into an adult capable of producing offsprings.

Summary/Note Making

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In Yeast, the division is unequal and small buds are produced that remain attached initially to the parent cell which eventually gets separated and mature into new yeast organisms (cells).
Members of the Kingdom Fungi and simple plants such as algae reproduce through special asexual reproductive structures such as zoospores (Chlamydomonas),.conidia (Penicillium), buds (Hydra) and gemmules (Sponge).
Vegetative propagation involves reproduction through vegetative (non sexual) plant structures.
Rhizome, sucker, tuber, offset, bulb are capable of giving rise to new offspring. These structures are termed vegetative propagules.

Summary/Note Making

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(Time Duration : 05 Minutes)

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12B01.3

Sexual Reproduction

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Recall Test

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Q.1 Clone is :

A) Morphologically identical individuals

B) Genetically identical individuals

C) Both A and B

D) None of the above

Q.2 Vegetative propagation is a type of:

A) Sexual reproduction

B) Asexual reproduction

C) Both A and B

D) None of the above

Q.3 Gemmules are seen in

C) Chlamydomonas

A) Hydra oligactis

B) Penicillium chrysogenum

D) Sponge

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Q4. Which of the following is not a vegetative propagule :

A) Rhizome

B) Bulb

C) Runner

D) Flower

Q5. Identify the wrong statement :

A) Asexual reproduction involves a single parent

B) Vegetative propagules are capable of producing new offspring

C) Vegetative propagules are not capable of producing new offspring

D) Gametogenesis takes place in sexual reproduction

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(Time Duration : 02 Minutes)

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Answers

Sol.1 C)

Sol.2 B)

Sol.3 D)

Sol.4 D)

Sol.5 C)

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Types of reproductive cycles

Primates

Menstrual Cycle:

Apes

Monkeys

Humans

Cyclical changes exhibited by females of primates during reproductive phase showing changes in activity of ovaries and hormones.

12B01.3 Sexual Reproduction

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Oestrus Cycle:

Non Primates

Cows

Sheep

Tigress

Deer

Cyclical changes exhibited by females of non primates during reproductive phase

12B01.3 Sexual Reproduction

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Seasonal breeders

Continuous breeders

12B01.1 Introduction To Reproduction

Mammals showing such cycles only during favourable conditions in their reproductive phase

Mammals reproductively active throughout their reproductive phase

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Events in Sexual Reproduction

Pre-fertilisation

Fertilisation

Post-fertilisation

a) Gametogenesis

b) Gamete transfer

b) Embryogenesis

a) The zygote

12B01.3 Sexual Reproduction

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12B01.3

CV 1

Pre-Fertilization Events

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Gametogenesis: is the process of formation of gametes (Male and female)

Isogametes / Homogametes

Isogametes of Cladophora (Alga)

Heterogametes

Male gamete

Female gamete

Antherozoid / Sperm

Egg / Ovum

Heterogametes of Humans

12B01.3 Sexual Reproduction

Gametes

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Haploid vs Diploid :

Haploid:

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Single set of chromosomes which is represented as ‘n’

Sperm (n)

Ovum (n)

Human Sex cells

12B01.3 Sexual Reproduction

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Diploid :

Sperm

Ovum

Double set of chromosomes which is represented as ‘2n’

Zygote (2n)

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12B01.3 Sexual Reproduction

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Cell division during gamete formation:

Haploid plant body (n)

Diploid organism (2n)

Mitosis

Haploid gametes (n)

Meiocyte (2n)

Meiosis

Haploid gametes (n)

e.g Monerans, Algae, Fungi, Bryophytes

e.g Pteridophytes, Angiosperms, most animals including humans

12B01.3 Sexual Reproduction

(n)

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Heterothallic/Dioecious

Sexuality in Organisms

Homothallic/Monoecious/Hermaphrodite

(Bisexual)

(Unisexual)

12B01.3 Sexual Reproduction

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Male flower

(Staminate)

Female flower

(Pistillate)

Stamen

Pistil

Stamen

Pistil

Sexuality In Plants:

e.g Cucurbits, Coconuts

e.g Date palms, Papaya

(Bisexual)

(Unisexual)

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e.g Earthworm

Bisexual

Unisexual

e.g Cockroach

Male

Female

Testes

Ovary

Testes sac with testes

Sexuality In Animals:

12B01.3 Sexual Reproduction

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Gamete transfer: In majority organisms male gamete is motile while female gamete is stationary

Flower 1

Flower 2

Bisexual plants

Unisexual plants

12B01.3 Sexual Reproduction

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12B01.3 Sexual Reproduction

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Concept Test

Ready for a Challenge

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Pause the Video

(Time Duration : 02 Minutes)

Q. Cells containing single set of chromosomes are called:

A) Haploid

B) Diploid

C) Polypoid

D) None of the above

Sol. A) Haploid

Explanation: Cells having single set of chromosomes are called haploid (e.g

Gametes) while the cells having double set of chromosomes are

called diploid (e.g Somatic cells)

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12B01.3

CV 2

Fertilisation

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Sperm

Ovum

Zygote

Fertilisation: is the process of fusion of gametes. Also termed as Syngamy &

results in formation of a diploid zygote

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12B01.3 Sexual Reproduction

23

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External Fertilisation

Types

Internal Fertilisation

Outside the body of female

Inside the body of female

Medium water

e.g Alga, Amphibians

e.g Humans

12B01.3 Sexual Reproduction

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Parthenogenesis:

Female gamete undergoes development to form new organism without fertilization

Honey bee

Egg

Unfertilised egg

Normal Process

Sperm

Ovum

Zygote

e.g Honey bee, Rotifers

12B01.3 Sexual Reproduction

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Concept Test

Ready for a Challenge

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Pause the Video

(Time Duration : 02 Minutes)

Q. Which of the following is true regarding parthenogenesis:

A) Fertilised female gamete undergoes development

B) Unfertilised female gamete undergoes development

C) Male gamete undergoes development

D) None of the above

Sol. B)

Explanation: Parthenogenesis is the process in which female gamete

undergoes development to form new organism without

fertilization.

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12B01.3

CV 3

Post-Fertilisation Events

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Zygote:

Diploid single cell

Fertilisation

Gametes

Mitosis

Haploid single/multicellular organism

Meiosis

Spores

Zygote

12B01.3 Sexual Reproduction

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Embryogenesis:

8 Cell Stage

Development of embryo from zygote

Cell division

Cell differentiation

Number of cells increased

Specialized tissues and organs formed

12B01.3 Sexual Reproduction

Zygote

2 Cell Stage

4 Cell Stage

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Oviparous

Based on development of zygote

Viviparous

Lay eggs (Fertilized/Unfertilized)

Give birth to young ones

e.g reptiles, birds

e.g Humans

Calcareous shell

Hatch out

12B01.3 Sexual Reproduction

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Flowering Plants:

Ovary

Fruit

Ovule

Seed

Stigma

Style

Ovary

Ovule

Pistil

12B01.3 Sexual Reproduction

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Seed

Pericarp

Zygote

Embryo

Fruit

12B01.3 Sexual Reproduction

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Concept Test

Ready for a Challenge

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Pause the Video

(Time Duration : 02 Minutes)

Q. Which of the following statement is true:

A) Embryogenesis is the development of embryo from zygote

B) Fusion of male and female gamete is fertilisation

C) Oviparous are egg laying

D) All of the above

Sol. D) All of the above

Explanation: All of the above statements listed are true

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Sexual reproduction involves the formation of male and female gametes which fuse together to form zygote.
Females of placental mammals exhibit cyclical changes in the activities of ovaries and accessory ducts as well as hormones during the reproductive phase.In non-primate mammals, it’s termed Oestrus cycle while in primate mammals it’s called Menstrual cycle.
Gametes are haploid while the zygote formed is diploid.
Morphologically identical gametes are called Isogametes/Homogametes while morphologically distinct gametes are called heterogametes.

Summary/Note Making

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Male gamete is called antherozoid or sperm while female gamete is called egg or Ovum.
Homothallic/Monoecious/Hermaphrodite denotes bisexual while

Heterothallic/Dioecious denotes unisexual condition.

In diploid organisms, Meiocyte (Gamete mother cell) undergo meiosis to form haploid gametes.
Pollination facilitates transfer of pollen grains to stigma where it germinates. Pollen tube is formed through which male gamete is delivered near egg.
Fertilization outside the body of organism is termed external fertilization while inside the body of organism is termed internal fertilization.

Summary/Note Making

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During embryogenesis, zygote undergoes cell division and cell differentiation. This increases the number of cells and modification of certain cells to form specialised tissues and organs.
In oviparous animals, the zygote develops outside the body of female parent while in viviparous the zygote develops inside the body of female parents.

Summary/Note Making

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(Time Duration : 03 Minutes)

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Reference Questions

NCERT : 12, 14, 15

Workbook: 1, 7