Page 10 - Reproduction in Animals

KEYWORDS
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KEYWORDS WHAT YOU HAVE LEARNTYOU HAVE LEARNT
KEYWORDS
WHAT
WHAT
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YOU HAVE LEARNT
WHAT YOU HAVE LEARNT
WHAT YOU
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ASEXUAL Ü There are two modes by which animals repro-
REPRODUCTION duce. These are: (i) Sexual reproduction, and
(ii) Asexual reproduction.
BINARY FISSION Ü Reproduction resulting from the fusion of male
and female gametes is called sexual
BUDDING reproduction.
Ü The reproductive organs in the female include
EGGS ovaries, oviducts and uterus.
Ü The reproductive organs in male include
EMBRYO
testes, sperm ducts and penis.
Ü The ovary produces female gametes called ova
EXTERNAL
and the testes produce male gametes called
FERTILISATION sperms.
Ü The fusion of ovum and sperm is called fertilisation.
FERTILISATION
The fertilised egg is called a zygote.
Ü Fertilisation that takes place inside the female
FOETUS
body is called internal fertilisation. This is
observed in human beings and other animals
INTERNAL
such as hens, cows and dogs.
FERTILISATION Ü Fertilisation that takes place outside the
female body is called external fertilisation. This
METAMORPHOSIS
is observed in frogs, fish, starfish, etc.
Ü The zygote divides repeatedly to give rise to an
OVIPAROUS ANIMALS
embryo.
Ü The embryo gets embedded in the wall of the
SEXUAL
uterus for further development.
REPRODUCTION
Ü The stage of the embryo in which all the body
parts are identifiable is called foetus.
SPERMS
Ü Animals such as human beings, cows and
dogs which give birth to young ones are called
VIVIPAROUS ANIMALS
viviparous animals.
Ü Animals such as hen, frog, lizard and butterfly
ZYGOTE
which lay eggs are called oviparous animals.
Ü The transformation of the larva into adult
through drastic changes is called
metamorphosis.
Ü The type of reproduction in which only a single
parent is involved is called asexual
reproduction.
Ü In hydra, new individuals develop from buds.
This method of asexual reproduction is called
budding.
Ü Amoeba reproduces by dividing itself into two.
This type of asexual reproduction is called
binary fission.

REPRODUCTION IN ANIMALS 75

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