Reproduction: It is a biological process in which organisms produce new organisms of their own kind.

Q. Why is reproduction necessary?

Reproduction is necessary because:-

  1. It ensures the continuity of species and keeps organisms from going extinct.
  2. It helps in the evolution of organisms by creating genetic variations.

Q. Do organisms produce exact copies of their own in reproduction?
During Reproduction DNA copies may be similar but may not be identical to the original.

Q. Why variations in the Reproduction of species is important?
Variation in Reproduction of species is important because:-
  • It helps in the development of species
  • It helps in the  evolution of species
  • It helps in disease resistance
  • It helps to adapt the changing environmental conditions.

Asexual Reproduction

  • It is a mode of Reproduction in which only one parent is involved to reproduce off-spring.
  • In this off-spring are exact copies of their parent.

Types of Asexual Reproduction
     1. Fission
     2. Budding
     3. Spore Formation
     4. Fragmentation
     5. Regeneration
     6. Vegetative Propagation

1. Fission :- It can be defined as the splitting of unicellular organisms into two or more daughter cells.
          a. Binary Fission:- Organisms divide into two equal daughter cells
              Examples:- Amoeba, Paramecium etc.

          b. Multiple Fission:- Organisms divide into many daughter cells
              Example:- Plasmodium etc.

2. Budding :- In this process, a daughter organism is formed from a small projection called Bud. The Bud takes nutrition from the parent body and gets mature. Fully matured Bud detaches from the parent body in new off-spring.
  • Example:- Yeast (unicellular), and Hydra (multicellular).

3. Spore Formation :- In this a plant produces 100s of spore which can grow into a new plant.
  • It is found in Multicellular organisms
  • Example:- Rhizopus, Fungi, Bacteria etc.

4. Fragmentation :- In this organism break down into several fragments. Later each fragment grows into a new individual.
  • It is found in Multicellular organisms.
  • Example :- Spirogyra.

5. Regeneration :- In this process organism repairs or regenerates the missing part of the body.
  • It is found in Multicellular organisms.
  • Example :- Starfish,  Planaria

Vegetative Propagation :- The process by which new plants are grown from the old parts such as roots, shoots and leaves without having any reproductive part.

1. Natural Vegetative Propagation :- Plants grow and develop naturally without human interference.
  • Example :- Sweet Potato, Potato, Bryophyllum.
2. Artificial Vegetative Propagation :- Plants grow and develop with the help of human interference.
  • a. Cutting b. Layering c. Grafting

Sexual Reproduction

  • The production of new organisms by the fission of male and female gamets.
  • This involves the exchange of chromosomes.
Q. Why sexual reproduction is important?
Sexual Reproduction is important because:- 
  • It creates more variation resulting in more adaptive to various changes in the environment.
  • It helps in the long time survival of species.

Q. What are the disadvantages of Sexual Reproduction?
Disadvantages of Sexual Reproduction:-
  • It takes time and effort to find a mate.
  • Fewer off-spring are produced.
  • Reproduction is not always successful.

Fertilization :- The process in which male and female gamet fuse together to form a zygote.

Sexual Reproduction in Flowering Plants :-

Pollination :- The process of transfer of Pollen Grain from Anther to Stigma is called Pollination.

1. Self Pollination :- Pollen grain directly falls from Anther to stigma on same flower.
2. Cross Pollination :- Transfer of Pollen grain from Anther to the stigma of one flower to the stigma of another flower.


Types of Flower:-
a. Unisexual Flowers :- Flowers that have either male or female reproductive structures.
     Example:- Papaya, Bittergourd, Pumpkin, Cucumber.

b. Bisexual Flowers :- Flowers that have both male and female reproductive structures.
     Example:- Rose, Hibiscus, lily, mustard.


Fertilization in Flower:-
After pollination, Pollen grain reaches to stigma. Pollen grains absorb water and sugar produced by Stigma and germinate the pollen tube through style reaches to the ovule of the ovary. Pollen tube contain two male gametes. Pollen tube release male gamet to embryo sac.
One male gamet fertilizes the secondary nucleus and the second male gamet fertilizes the egg and forms the Diplyd zygote.


Q. Why Fertilization in Flower is also known as Double Fertilization?
Since there are two male gametes involved in the process of Fertilization of flowers, therefore it is also called double fertilization.


Sexual Reproduction in Human Beings :-

Structure of the Male Reproductive System
1. One Pair of Testis
  • In human beings, there are Abdominal cavities inside the serotum. 
  • The testis is also called the male sex organ and produces Sperm and male sex hormone known as Testosterone (Androgen).
  • Testosterone is responsible for the development of the Secondary sexual character of males.

2. Epididymis
  • It is tube-like and coiled structure. 
  • It helps in the maturation of sperm to become mature and develop motility.

3. Vas-deference (Sperm Duct)
  • It is one pair and tube-like structure.
  • It carries sperm from the Testis to the seminal vesicle.

4. Seminal Vesicle
  • It is a glandular structure. 
  • It secretes seminal gland fluid. 
  • Seminal fluid contains fructose and protein. 
  • Seminal vesicles provide nutrition to developing sperm.

5. Copulatory Organ
  • It is an external male genital organ. 
  • It transfers sperm into to vagine of the female during Copulation.

6. Prostate Gland
  • It is one pair and located at the lateral side of Urethra. 
  • The prostate gland secretes Acidic fluids.

7. Cowper's Gland
  • It is located on the lateral side of the Urethra and secretes basic fluids.
Note:- The reproductive system of the Human male is connected with the Excretory System   


Structure of Female Reproductive System :-

1. One Pair Ovary
  • It is located inside the abdominal cavity, the lateral side of the Uterus.
  • It produces ovum, Oestrogen, and Progesterone.
  • Oestrogen hormones are responsible for the development of the secondary sexual character of females.

2. One Pair Oviduct
  • It is a tube-like structure.
  • The first part of the oviduct is called the oviducal funnel.
  •      a. Many cilia are present in it.
  •      b. Cilia capture the ovum from the ovary.
  • The second part of the oviduct is called the Fallopian tube, also known as the Sight of Fertilization.

3. Uterus
  • It is the Longest part of the female Reproductive System.
  • It is pear-shaped and muscular structure.
  • The inner layer of the Uterus is called Endometrium.
  • Inside it Embryo grow and develop.

4. Vagina
  • It is a tube-like structure.
  • Also called the Birth canal.
  • The lower part of the Uterus opens into vegina.


Placenta :- An organ that connects the develping fetus to the Uterus wall.
Function of Placenta :-
  • It provide nutrition from mother blood to embryo.
  • It provide oxygenated blood from mother to embryo.
  • It remove excratory substance from embryo.
  • It secret many hormone.


Birth Control Method :-

1. Surgical Method 
     i). Vasectomy :- Male surgical method. In this small portion of Spermduct is cut and tied properly with surgical thread.
     ii). Tubectomy :- Female surgical method. In this small portion of Fallopian tube si cut and tied properly with surgical thread.

2. Hormonal Method
Oral pills consist of Oestrogen and Progestron Hormone are used. Prevent release of ovum. Oral pills intake only by female.

3. Barrier Method
Barrier are used for prevention of fertilization. It is used in IUD (Intra Uterine Device).


Sexually Transmitted Disease :-

  • These disease are transmitted by the sexualy contact betweeen the infacted person and the healthy person.
  • Caused by viruses and bacteria.
Example :- AIDS (Acquired Immuno Deficiency Syndrome), caused by HIV (Human Immuno Virus)