Biology
Reproduction in animals
1-Animals such as hen, frog, lizard and butterfly which lay eggs are called oviparous
animals.
2-Animals such as human beings, cows and dogs which give birth to young ones are
called viviparous animals.
3-Viviparous animals have external ears and epidermal hairs on their skin.
4-There are two modes by which animals reproduce. These are Sexual reproduction
and asexual reproduction.
5-The type of reproduction where fusion of gametes does not take place is called
asexual reproduction
6-Budding, fission etc are some common methods of asexual reproduction. Budding
is observed in Hydra and binary fission is observed in Amoeba.
7-Asexual reproduction is common in micro-organisms.
8-Reproduction resulting from the fusion of male and female gametes is called sexual
reproduction.
9- The reproductive organs of a male consists of testes, sperm ducts and penis.
10- The reproductive organs of a female consists of ovaries, oviducts and uterus.
11- The ovary produces female reproductive cells called ova and the testes produces
the male reproductive cells called sperms.
12- The fusion of ovum and sperm is called fertilization. The fertilized egg is called a
zygote.
13-Fertilization that takes place outside the female body is called external fertilization
and that which takes place inside the female body is called internal fertilization.
14- Internal fertilization is observed in human beings and other animals such as hens,
cows, dogs etc.
15- External fertilization is very common in aquatic animals such as fish, starfish etc.
it is also seen in frogs.
16-The stage of the embryo in which all the body parts are identifiable is called foetus.
17-The transformation of the larva into adult through drastic changes is called
metamorphosis.
18-Due to fertilization offsprings get some characters from their parents
19-The zygote divides repeatedly to develop into an embryo.
20-The embryo gets embedded in the wall of the uterus for further development.