This ppt includes Chapter 1 Reproduction in organisms (CBSE) class XII. It will be helpful for a quick reference. *** there are a few mistakes please make the following changes slide 27 , Earthworm is Bisexual( hermaphrodite). slide 28 , Pistillate - flowers with pistil. slide 29 and slide 30 - ignore that .

1. CHAPTER 1
REPRODUCTION IN ORGANISMS
PUSHPINDERJEET KAUR
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2. REPRODUCTION
It is defined as a biological process in which an
organism gives rise to young ones similar to itself.
The offspring grow , mature and in turn produce
new offspring.
 SIGNIFICANCE OF REPRODUCTION-
 It ensures continuity of the species.
 It leads to variation among individuals.
 Maintain life on earth.
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3. LIFE SPAN – The period from birth to natural death of an
organism.
It may be as short as a few days or as long as a few thousand
years.
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4. LIFE SPAN OF AN ORGANISM USUALLY
INCLUDES FOUR PHASES:
PHASE 1 •Juvenile Phase
PHASE 2 •Reproductive Phase
PHASE 3 •Ageing and Senescence
PHASE 4 •Death
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5. TYPES OF REPRODUCTION
REPRODUCTION
ASEXUAL
REPRODUCTION
SEXUAL
REPRODUCTION
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6. ASEXUAL REPRODUCTION
Asexual Reproductive Structures-
Fission
Budding
Fragmentation
Regeneration
Sporulation
Eg; Conidia, Spore,zoopores
Vegetative reproduction
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10. GEMMULE IN SPONGES
*Gemmule is a type of internal
bud formed in sponges to pass
the unfavourable season.
*It is an asexually reproduced
mass of cells, that is capable of
developing into a new organism
i.e., an adult sponge.
*Gemmules are resistant
to desiccation (drying out),
freezing, and anoxia (lack
of oxygen) and can lie around
for long periods of time.
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12. ASEXUAL REPRODUCTION SEXUAL REPRODUCTION
 Single individual is involved
 Offsprings are genetically and
morphologically identical to the
parents.
 Only mitosis is involved in such
type of reproduction.
 It is a simple and fast process
 It does not play a vital role in
evolution.
 It is uniparental with or without
formation of gametes.
 Two individual are involved
 Offsprings are not genetically
and morphologically similar to
their parents.
 Mitosis and meiosis both are
involved in this type of
reproduction.
 It is a complex and slow
process.
 It plays a vital role in
evolution.
 It involves formation and
fusion of gametes.
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13. VEGETATIVE PROPAGATION
1.BULB
2.TUBER
3.RHIZOME
4.Bulbil
5.LEAF BUD
6.OFFSET
7.SUCKER
8.RUNNER
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14.  RUNNER - It is an aerial weak stem running along the
surface of the soil. New buds and roots are formed at the
nodes.
 Sucker - It is a shoot that arises from an adventitious bud
on underground root or underground stem. Eg; Mint,
Chrysanthemum.
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15.  Tuber - It is an underground swollen stem.
 Bulb - It is an underground stem with fleshy leaves
attached to it. Eg; Onion , Bulb
 Rhizome - A plant stem that grows horizontally
underground.
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16. Offset - Thick, fleshy stem in aquatic plants
which run horizontally to the surface of the
water.Eg; Water Hyacinth
Bulbil-Fleshy buds act as vegetative
propagule.
Eg ; Agave
Leaf Buds -Eg; Bryophyllum
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17. RECAP (ASEXUAL REPRODUCTION)
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18. REPRODUCTION IN FLOWERING
PLANTS
Annual – The plant which completes its
life cycle within one year and then dies.
Eg. Peas
Biennial - The plant which completes its
biological life cycle in two years. Eg.
Onion
 Perennial - The plant that lives for more
than two years. Eg. Banana, Mango
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21. WATER HYACINTH
 One of the most invasive weeds –TERROR OF
BENGAL
 Grows wherever there is standing water
 Drains oxygen from water- leads to death of fishes.
 Introduced in India because of its pretty flowers &
shape of leaves
 Vegetative propagation occurs at a phenomenal
rate
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22. OESTROUS CYCLE VS MENSTRUAL CYCLE
Oestrous cycle Menstrual cycle
The cyclic changes which occur
in non primate mammals during
reproduction is called Oestrous
cycle.
Interval between two consecutive
cycles varies between a few
months to over a year.
Females are sexually active only
during oestrous phase of their
cycle , referred to as being ‘in
heat’.
Eg; Cow , dog , tiger , deer etc
The cyclic changes which occur
in primate mammals during
reproduction is called Menstrual
cycle.
Interval between two consecutive
cycles is about 4 weeks.
Females can be sexually active at
any time in their cycle.
Eg; monkey, apes and humans
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23. ON THE BASIS OF TIME OF BREEDING,
ANIMALS ARE OF TWO TYPES:
Seasonal Breeders: They reproduce at
particular period of the year such as
frog, lizards, most birds, deer, etc.
Continuous Breeders: These animals
continue to breed throughout their
sexual maturity. Examples are honey
bee, queen, poultry, rabbit, mice,
cattle, etc.
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24. SEXUAL REPRODUCTION
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25. PRE FERTILISATION EVENTS
 A) Gametogenesis-
i) Spermatogenesis- formation of sperms
ii) Oogenesis – Formation of ova
 Types of gametes-
i) Homogametes or isogametes- the two gametes
similar in appearance ,can not categorise into
male and female gametes. eg. Cladophora
ii) Heterogametes - two morphologically distinct
gametes . Male gamete is called antherozoid
or sperm. Female gamete is called the egg or
ovum. eg. Fucus, Human being 25
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26. TYPES OF GAMETES
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27. BISEXUAL
(Cockroach)
UNISEXUAL
(Cockroach)
MONOECIOUS
(Chara)
DIOECIOUS
(Marchantia)
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28. SEXUALITY IN ORGANISMS
 Homothallic and monoecious - terms used to
describe bisexual condition of plant.
 Heterothallic and dioecious - terms used to
describe unisexual condition of plant.
 Staminate - unisexual male flower bearing
stamens .
 Pistillate - unisexual female flower bearing
stamens.
 Monoecious - both male and female flowers may
be present on the same individual. Eg. cucurbits and
coconuts.
 Dioecious - both male and female flowers may be
present on separate individuals. Eg. papaya and
date palm.
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29. CELL DIVISION DURING GAMETE FORMATION
 Cell division is of two types Mitosis and Meiosis.
Diploid parent
?
Haploid gamete
Haploid parent
?
Haploid gamete
Meiocytes
(gamete mother cell)
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30. Does Meiosis never occur in organisms
that are HAPLOID?
Haploid
Parent (male)
Haploid parent
(female)
Gamete
(n)
Gamete
(n)
ZYGOTE
(2n)
Zygote undergoes meiosis to
Form haploid organism
similar to parents 30
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31. B) GAMETE TRANSFER
In majority of organisms – Male gamete is motile
Female gamete is non-motile
Few fungi and algae – Both male and female gametes are
(Algae, bryophytes motile
and Pteridophytes) - They need medium.
- A large number of male gametes are
released in compared to the female gamete to
compensate the loss of male gamete during the transport.
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33. POLLINATION
Transfer of pollen grain from anther
to the stigma of a flower.
Pollination can be self or cross pollination.
Pollen grain
germinates on the
stigma and pollen
tube carries the
male gamete near
the egg.
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34. FERTILISATION
Pollinatio
n
Formation of
pollen tube
Fusion of male
gamete and egg –
fertilisation or
Syngamy
F
or
m
at
io
n
of
Z
Y
G
O
T
E
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35. PARTHENOGENESIS
Parthenogenesis is derived from the Greek words for
“virgin birth,”
The process of formation of organisms without fertilisation
or fusion of gametes is called parthenogenesis.
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37. POST FERTILISATION
 ZYGOTE
 Embryogenesis (MITOSIS)
 EMBRYO
Haploid
Spores
HAPLOID
INDIVIDUAL
MEIOSIS
DIPLOD
INDIVIDUALS
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39. CHANGES IN FLOWERING AFTER
FERTILISATION
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