This document discusses and compares sexual and asexual reproduction. It describes the main types of asexual reproduction, which include binary fission, budding, spore formation, vegetative reproduction, and rejuvenation. These methods allow organisms to rapidly increase numbers with genetically identical offspring. The document then explains sexual reproduction, which involves the fusion of male and female gametes during internal or external fertilization to produce offspring with genetic variation. Key differences between sexual and asexual reproduction are also outlined.

1. Introduction

2. Sexual and Asexual Reproduction
•Reproduction is a production of a new generation of
individuals (offspring) from pre existing ones
(parents).
•The importance of reproduction is to ensure the
continuity or perpetuation of the species.
•There are two types of reproduction, namely sexual
and asexual.

3. Asexual Reproduction
•This is a rapid method of increasing the number of
new individuals.
•The new individuals are formed from one parent
and they are genetically identical to each other and
to the parent.
•There are five major types of asexual reproduction:
a. Binary fission
b. Budding
c. Spore formation
d. Vegetative reproduction
e. Rejuvenation

4. •Binary fission is seen in bacteria, Amoeba and
Paramecium.
•The unicellular organism divides into two equal
parts (daughter cells)
Binary fission
Binary fission in Amoeba

5. •Budding is seen in yeast and Hydra.
•The parent produces an outgrowth or bud which
detaches to become a new individual.
Budding
Budding in yeast

6. •Spore formation is seen in
bacteria, fungi, mosses and
ferns.
•Spores are formed in spore –
bearing structures called
sporangium.
•Spores are generally very
small and light, which helps
them to be dispersed by wind
and water.
•Each spore can develop into a
new individual.
Spore formation in
pin mold (Mucor)
Spore formation

7. •This type of asexual reproduction is seen in many
flowering plants.
•Part of a plant (root, stem, leaf or bud) detaches and
grows into a new plant.
Description Example
Runner
•A slender shoot that arises in the axil
of a leaf and grows horizontally on
the surface of the grounds.
•The runner bears root and becomes
independent before the parent plant
dies.
•Grass, strawberry
Insert image
Runner of grass
Vegetative reproduction

8. Bulb
•A bulb has a short stem and fleshy
leaves containing food (mainly sugar)
•It is surrounded by brown scaly leaves.
•New shoots arise from buds in the axils
of the fleshy leaves.
•Onion, lilies
Onion bulb
Rhizome
•A horizontally growing underground
stem which stores food.
•It produces lateral buds, some of which
develop into shoots.
•When the old rhizome dies, the new
shoots become independent plants.
•Canna, Ginger
Rhizome of ginger

9. •Corm
•A short, vertical, underground
stem swollen with food
reserves.
•It is protected by scaly leaves.
•Buds are located at the axils of
these leaves.
•Cocoyam, water chestnut
Corm of cocoyam
Stem tuber
•The swollen ends of
underground stems.
•New shoots sprout out from
axilary buds or “eyes”
•Potato, artichoke
Tuber of potato

10. •Rejuvenation refers to the replacement of parts of an
organism that are lost due to injury.
•Rejuvenation is a form of asexual reproduction if it
results in two or more individuals in which there was
only one before.
•Animals such as sponges, flatworms and starfish are
capable of rejuvenating complete organisms from parts
of their bodies.
•If a sponge is chopped into hundred parts, a hundred
new sponges are generated. A starfish cut into half
gives two starfish.
Rejuvenation

11. Rejuvenation in Planarian (a flatworm)
•Rejuvenation is common in plants. It is called
vegetative propagation. Whole plants can be grown
from cuttings and grafts.

12. Sexual Reproduction
•Sexual reproduction is the production of offspring by
the fusion of specialized sex cells or gametes.
•The male gamete (sperm) fuses with the female gamete
(ovum or egg) by a process known as fertilization. This
results in the formation of a zygote. The zygote develops
into a new individual.
•There are two types of fertilization, internal and
external.

13. •The internal fertilization, the sperm are deposited in
the female reproductive tract and fertilization occurs
within the body of the female. The zygote develops
internally and live individuals are born. Internal
fertilization occurs in insect, reptiles, birds and
mammals.
•The external fertilization, which is limited almost
entirely to aquatic organisms, sperms and eggs are
shed into the water in great numbers simultaneously.
Only a small number of eggs are fertilized by the
sperms. External fertilization occurs in most fish,
amphibians and aquatic plants.

14. Advantages of internal fertilization over
external fertilization
•The eggs have a better chance of being fertilized by the
sperms. Thus, there is less wastage of gametes.
•The developing young receives nourishments from the
female parent before the birth.

15. Comparison between sexual and
asexual reproduction
Asexual reproduction Sexual reproduction
Similarity
•Involves the production of a new generation of
individuals of the same species.

16. Differences
•One Number of parents
involved
•Usually two
•No Gametes involved •Yes, two types:
Male, female
•Identical with
parents
Genetic make–up of
offspring
•Different from
parents and they
show genetic
variation
•Produces large
numbers of
offspring
Offspring •Produces fewer
offspring
Rapid form of
reproduction
Speed of reproduction •Less rapid from
reproduction