There are two
types of reproduction;
1) Asexual reproduction 2)
sexual reproduction
Asexual reproduction in animals: The type of reproduction in
which male and female sex cells are not involved is called asexual
reproduction. Small pieces from their bodies separate and grow in to
new animals like earthworm, sponges etc.
Asexual reproduction in
plants:
It is a kind of reproduction in which only
one parent is involved. In this kind of reproductionno mixing of
male and female gametes (sex cell).
Asexual reproduction in plants is also known as vegetative
reproduction or vegetative propagation.
a) Cutting:Cactus plants bud cut from
the main plants and fell down on the soil where they grow in to a new plant.
Example rose andjasmine etc.
b) Grafting:In this method cutting s are grafted on
other plants of same kind to improvequality and quantity
of yield.
c) Layering:When the branch of some plants is buried in
the soil they develop roots and finally a new plant is formed.
And finally the branch goes under the soil cut off from the main
plant which grows independently.
Tuber:Potato tubers have eyes or buds
on it. When the tubers are grown, these eyes develop into new plant.
Sexual Reproduction:
The
type of reproduction in which sex cell are involved is called
sexual reproduction. In this reproduction sex cells of male animals or plant
reach the sex cell of the female.
The both cells together
to make a new bigger cell called zygote.
The process of uniting male and female sex cells is called as fertilization.
Sex organ of a plant present in the flowers.
Generally a flower contains both types of sex organ.
a) Sepals (Calyx):These are green leaf like
parts which protect the inner parts in bud condition.
b) Petals (Corolla):These are brightly colored leaf
which attracts the insects towards them.
c) Stamen (Androecium):This is the male
sex organs of the flowers.
The lowest part stamen of this is called filament.
The upper box like structure of stamen is called anther. Another
is filled with male sex cells is called pollen grains.
d) Carpals (Gynoecium):Generally a single
carpel is present in the center of the flower.
Carpalis female sex organ of the flower. A typical
consists of three parts Stigma, Style, and Ovary.
In Ovary female sex cell presented.
Pollination
The transfer of pollen grains
from the anther to the stigma of the carpel is
called pollination.
There are two types of pollination.1) Self Pollination 2) Cross pollination
When pollens from the anther are transferred to the
stigma of the same flower, the process is called self-pollination.
When the transfer of pollen grains from the antherto
the stigma of a flower on another plant of the same species is called cross
pollination.
For pollination the plants must be of the same species. For
example pollens from a sunflower plant can pollinate another sunflower
plant only.
Cross pollination is brought about the different agents
called pollinators. These agents include animals especially insect,
wind and water.
……….is the productive part in the flowering plants.
a) Root
b) Stem
c) Flower
d) Branch
Self-pollination occurs between ……………… a) Same or different flower of the same plant b) Flowers of different plants c) Different flowers d) Same flower
