NATURE HAS INVENTED REPRODUCTION AS A MECHANISM TO MOVE FORWARD. AS A LIFE FORCE THAT PASSES RIGHT THROUGH US AND MAKES US A LINK IN THE EVOLUTION OF LIFE

1. REPRODUCTION
IN ANIMALS

2. Prepared by-
Pratyusha Ranjan Sahoo and Spriha Bairagi
Regional Institute of Education (NCERT), Bhubaneswar

3.  REPRODUCTION IN ANIMALS
 MODES OF REPRODUCTION
 SEXUAL REPRODUCTION
 REPRODUCTION ORGANS – male and female
 FERTILISATION – internal and external
CONTENTS OF THIS PRESENTATION

4. “NATURE HAS INVENTED REPRODUCTION AS A
MECHANISM TO MOVE FORWARD. AS A LIFE
FORCE THAT PASSES RIGHT THROUGH US
AND MAKES US A LINK IN THE EVOLUTION OF
LIFE.”
- Louis Schwartzberg
WHOA
!

5. WHAT IS REPRODUCTION ?
 Reproduction is a process where an organism produces others of
the same kind.
 There are two types of reproduction in living organism –
- ASEXUAL
- SEXUAL
 ASEXUAL REPRODUCTION – the production of a new organism
from a single parents without the involvement of gametes or sex
cells. Eg- Binary fission in Amoeba.
 SEXUAL REPRODUCTION – The production of a new organism
from two parents by making use of their sex cell or gametes is called
sexual reproduction . Eg- Human, frog etc.

6. MALE REPRODUCTIVE ORGANS
(human)

7. The male reproductive system consists of :
Testicles (testes): A pair of oval-shaped organs masked in a pouch called the scrotum.
They are responsible for the production of sperms and the male hormone testosterone.
Scrotum: It is a sac-like organ that hangs below the penis and behind it. It is the houses
of the testicles, or testes, and maintains a temperature that is required for the
production of sperm by it.
Vas deferens: The sperms produced in testes are stored in a tube called the epididymis.
Here the sperms get matured and pass to urethra through the muscular tube called
vas deferens.
Accessory glands: This includes three glands, namely seminal vesicles, prostate gland,
and Cowper’s gland. The secretions from the three glands mix to form a fluid called
semen. Semen nourishes the sperm, increases the volume and helps in lubrication.
Penis: Penis is a cylindrical tube which serves as both reproductive organ and an
excretory organ. It delivers sperms into the vagina during sexual intercourse.

8. FEMALE REPRODUCTIVE ORGANS
(human)

9. The female reproductive system is active before, during and after fertilization as well. It
consists of the following parts:
A pair of ovaries: Ovaries produce and store ovum in them. They also produce a female
hormone called estrogen.
Fallopian tubes (Oviducts): They are the site of fertilization. They connect ovaries with
the uterus.
Uterus: Uterus is the site of development for the embryo.
Vagina: It is the part which connects the cervix to the external female body parts. It is the
route for the penis during coitus as well as a fetus during delivery.
Female reproductive system has two functions –
Production of female gamete called ovum/egg.
Providing nutrition and protecting the developing embryo.
During puberty, eggs in the ovaries start to mature. One of the ovaries releases the
matured ovum in every 28 to 30 days and is called ovulation.

10.  sperm, also called spermatozoon,
plural spermatozoa, male reproductive cell,
produced by most animals.
 The sperm is comprised of a head, neck, middle
piece and tail. The whole body of sperm is
enveloped by the plasma membrane.
Structure of Sperm
The Head contains acrosome apically, which contains
enzymes that facilitate the entry of sperm into the
ovum. It is followed by an elongated nucleus (haploid)
The middle piece has multiple mitochondria, that
provide energy for the movement of sperms
The tail is a flagellum that protrudes out of the cell body
and is responsible for the vigorous motility of sperms.
The tail helps sperms in swimming so that they can
reach towards the ovum
Around 200-300 million sperms are ejaculated at once
MALE AND FEMALE GAMETES

11.  Ovum is the female gamete
 Like the sperm , an egg is also an single cell
 Produced in the ovary
 the sperm is the smallest cell in the human body
while the ovum is the largest.
 Non-motile
 The largest cell in the human body
 No external segmentation like in case of sperms
(head, middle piece, tail)
 In human beings , a single matured egg is
released into the oviduct by one of the ovaries
every month. Uterus is the part where
development of the baby takes place

12.  Fertilisation: The fusion of a sperm with an egg is called fertilisation.
During fertilisation, the nuclei of the sperm and the egg fuse to form a single
nucleus. This results in the formation of a fertilised egg called Zygote.
 Fertilisation may be:
1) Internal Fertilisation: Fertilisation which takes place inside the body of
the female is called internal fertilisation. For example: as in humans, dogs,
cows, birds etc.
2) External Fertilisation: Fertilisation which takes place outside the body of
the female is called external fertilisation. It is very common in aquatic animals,
such as fish, starfish and amphibians (animals who live in water as well as on
land such as frog).
3) IVF or in vitro Fertilisation: The fertilisation of an egg that takes place
outside the body in a test tine or in any other, apparatus is known IVF or in
vitro fertilisation.
Test Tube Babies: In this technique freshly released egg and sperms are
put together for a few hours for IMF. In case fertilisation occurs, the zygote is
allowed to develop for about a week and then placed in the uterus of the
mother. Complete development takes place in the uterus and the baby is born
like any other normal baby. The term test tube babies is misleading, because
babies cannot grow in test tube
FERTILISATION

13. SUMMARY
 There are two modes by which animals reproduce. These are – 1) Sexual
reproduction 2) Asexual reproduction
 Reproduction resulting from the fusion of male and female gametes is called
sexual reproduction.
 The reproductive organs in the female include ovaries, oviducts, and uterus.
 The reproductive organs in male include testis, sperm ducts, and penis.
 The ovary produces female gametes called ova (singular) ovum (plural) and
testes produce male gametes called sperms.
 The fusion of ovum and sperm is called fertilisation. The fertilised egg is called
zygote.
 Fertilisation that takes inside the female body is called internal fertilisation. Eg-
humans, cows, hens and dogs.
 Fertilisation that takes place outside the female body is called external
fertilisation. This is observed in frogs, fish, starfish, etc.