BIOLOGY PROJECT
Reproduction-‘Re’ means ‘again’ and
‘Production’ means ‘make of its own kind’.
Reproduction is a biological process by which
an organism reproduces an offspring that is
biologically similar to the organism. It is a
characteristic of a living beings and one of the
basic features of the life. Reproduction takes
place because for the survival of human
beings and so that spices do not get extinct,
by this way they also maintain their number.
Reproduction enables and ensures the
continuity of species, generation after
generation. It is the main feature of life on
earth.
1. Types of Reproduction
There are basically two types of reproduction:
1. Asexual Reproduction
2. Sexual Reproduction
3.
Asexual Reproduction-Asexual reproduction
refers to the type of reproduction in
which only a single organism gives rise
to a new individual, without the fusion of
sex cells. The new individuals produced are
genetically and physically identical to each
other, i.e., they are the clones of their
parents. Asexual reproduction is observed in
both multicellular and unicellular organisms.
Sexual Reproduction- Sexual reproduction
is a type of reproduction that involves
the production of an offspring by the
fusion of male and female gametes. This
process is usually slow and complex
compared to asexual reproduction. The
offspring produced has a mix of features of
both parents. Thus, they can evolve along
with the changing climatic conditions.
Humans and many multicellular organisms
exhibit a sexual mode of reproduction.
Binary Fission- Binary fission means "division
into two". It is the simplest and most
common method of asexual reproduction.
Binary fission, asexual reproduction by a
separation of the body into two new bodies.
In the process of binary fission, an organism
duplicates its genetic material, or
deoxyribonucleic acid (DNA), and then
divides into two parts (cytokinesis), with
each new organism receiving one copy of
DNA.
Multiple Fission- Multiple fission Division of the
nucleus, simultaneously or successively, into
a number of daughter nuclei, followed by
division of the cell body into an equal number
of parts, each containing a nucleus. In this
process, nucleus divides repeatedly to
produce large number of nuclei. Many
individuals are formed by splitting of a single
parent cell.
Budding- In this, a small bud-like outgrowth
gives rise to a new individual. The outgrowth
remains attached to the organism until it is
fully grown. It detaches itself and lives as an
individual organism. Budding is a type of
asexual reproduction in which a new organism
develops from an outgrowth or bud due to cell
division at one particular site.
Fragmentation- In this, the parent organism
splits into several parts and each part grows
into a new individual. Fragmentation in
multicellular or colonial organisms is a form of
asexual reproduction or cloning, where an
organism is split into fragments. Each of these
fragments develops into mature, fully grown
individuals that are clones of the original
organism.
Vegetative Propagation-Vegetative
reproduction is any form of asexual
reproduction occurring in plants in which a
new plant grows from a fragment or cutting
of the parent plant or specialized
reproductive structures, which are
sometimes called vegetative propagates.
Vegetative Propagation occurs with root,
leaves and stem. In this process, no seed
produced.
Its types-
1. By underground stem- Underground stems
are modified plants that derive from stem
tissue but exist under the soil surface. They
function as storage tissues for food and
nutrients, propagation of new clones, and
pronation.
2. By aerial Stem- Stems grow above the
ground and have characteristic erect or
vertical growth. Aerial stems
are modifications of stems under growth
conditions to perform specific functions such
as storage of food, structural support,
climbing, and vegetative propagation.
3. By root- Plants such as sweet potato and
dahlia have fleshy tuberous roots with
adventitious buds. These buds when
detached and planted in soil, can give rise
to new plants.
4. By Leaves- Some plants such as
Bryophyllum and Kalanchoe produce
adventitious buds at the margin of the bay.
When the leaf falls on moist soil, the buds
develop into small plantlets. The fleshy
leaves supply food and water to the
plantlets as they grow. The plantlets grow
into independent plants on separation from
the leaf.
5. Advantages-
The Plants cultivated are genetically
identical to their parents.
Plants can be cultivated faster as compared
to growing them from seed.
6. Disadvantages-
No new varieties can be produced.
Skilled people are required and are often
expensive as compared to seed
propagation.
Sexual Reproduction
Types of Flowers
1. Complete Flowers-Flowers in which four
whorls are present.
2. Incomplete Flowers-Flowers in which one or
more whorls are missing.
3. Neutral Flowers-Neutral flowers do not
contain either androecium or Gynoecium.
Types of Pollination (from book)
Cross pollination- by wind- (from image)
Cross pollination- by insect- (book)
Cross pollination- by water- (from image)
Cross pollination- by animal- (from image)
Fertilization- The fusion of a sperm with an
egg is called fertilization. During fertilization,
the nuclei of the sperm and the egg fuse to
form a single nucleus. These results in the
formation of a fertilized egg called Zygote.
Fertilization is the fusion of male and female
gametes to produce a new organism. Zygote
is one celled stage of an individual which
divides to form embryo.
Seed formation- A seed is formed when
fertilized ovule divides by mitosis. It stores
food and has the potential to develop into a
new plant under optimal conditions. In the
typical flowering plant, or angiosperm, seeds
are formed from bodies called ovules
contained in the ovary, or basal part of the
female plant structure, the pistil.
Fruit formation- (from image) Fruit protect
seed from insects, diseases and extreme
climatic condition.
Germination- The process by which a mature
seed undergoes activation after a period of
dormancy and develops the first tiny root and
shoot of the plant by sprouting is called
germination. Water, a suitable temperature
and oxygen are required for seeds to
germinate. Example- sprouting of a seedling
from a seed of an angiosperm or
gymnosperm.
Thank You
Do in project by tomorrow.
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Jai Hindu rashtra
