This document discusses reproduction in various forms of life. It describes asexual reproduction, which does not involve sex cells and occurs through mechanisms like budding, fragmentation, and regeneration. It produces offspring that are genetically identical to the parent. Sexual reproduction involves the union of egg and sperm to produce offspring with genetic variation. It summarizes the process of sexual reproduction in flowering plants, including pollination, fertilization, fruit and seed development, and seed germination.

1. Reproduction in some forms of
life

2. Reproduction
 Forms the next generation of species
 The means to continue life (perpetuation
of species)
 May be sexual or asexual

3. Asexual
reproduction
Sexual
reproduction
 Does not involve
gametes or sex
cells
 Occurs in many
forms and is
performed by many
lower forms of
organsims,
including plants
 No genetic variation
in organisms
 Involves sex cells
 The sperm and the
egg unite to form a
zygote
 Characteristic of
many organisms,
including plants,
animals and
humans
 Increases genetic
variation among

4. Examples of Asexual
reproduction
 Fission – one cell divides into two either
longitudinally, transversely or even
diagonally
E.g. Algae Volvox and Ulothrix, paramecia,
amoeba, bacteria and corals
 Fragmentation – pieces of an organism may
break off and develop into whole organisms
Colonies of algae, sea anemone, comb
jelly, flatworms

5. Paramecium

6.  Budding – cells in some areas of an
organism’s body organize themselves to
form new individuals or buds
Hydra (freshwater polyp)
 Parthenogenesis (virgin birth) – an egg
possessing diploid chromosomes develops
into an adult without being fertilized
Daphnia, rotifers, snails, honeybees and
sea urchins
Examples of Asexual
reproduction

7. Budding in Hydra

8.  Paedogenesis – smaller larvae develop
from bigger larvae and grow up to
become adults
Flukes, taperworm, ascaris
 Regeneration – demonstrated by sea
stars; when a sea star is cut into pieces,
such that each arm has aportion of the
central disk, each piece grows the rest of
the central disk and the for other arms
Examples of Asexual
reproduction

9. Sea stars

10. Conjugation
 Sexual reproduction in lower forms of life
 Genetic material (not necessarily gametes)
is transferred between two individuals
through a protoplasmic bridge before
allowing autotomy (voluntary separation of
a body part) to take place
Paramecium, bacteria and cyanobacteria,
fungi

11. Examples of Asexual
reproduction
 Common bread mold (amag) – reproduces
through spores encased inside a capsule-
like container called sporangium
 Mosses and ferns – spore-producing plants
Spores – primary structures responsible
for asexual reproduction in mosses and
ferns

13. Asexual or Vegetative Reproduction
in Flowering Plants
Vegetative
Reproductio
n
Natural
Runners
Leaf
reproduction
Tip layering
Artificial
Layering
Grating and
Budding
Cutting

14. Natural Vegetative Reproduction
 Runners – grow along the ground from the
parent plant; forms adventitious roots and
shoots at the tips
 Strawberry
 Tip layering – allows their aerial stems to arch
downwards so that their tips touch the ground
 Blackberry, raspberry and spider plant
 Leaf reproduction – new plants develop along
the margins of their leaves
 katakataka

15. Artificial Vegetative Reproduction
 Cutting – portions of stems and roots are
removed and transferred to loose, damp soil or
sand
 Herbaceous and woody plants such as rose
 Layering – stimulates the growth of roots on a
stem; a stem is buried in the ground then cut
when roots are formed
 Grafting and budding – splicing together of two
stems or the union of their two cambium layers

16. Sexual Reproduction in Flowering
Plants: Floral Parts
 Calyx – collection of sepals
 Corolla – collection of petals
 Stamen – male reproductive part
Filament – slender stalk
Anther – produces colored grains called
pollen, which contains sperm nuclei

17.  Pistil/Carpel – female reproductive part
Stigma – sticky topmost part
Style – slender stalk that supports the
stigma
Ovary – swollen base
Ovules – found inside the ovary

19. Stages of Sexual Reproduction in
Plants
a. Formation of Gametes
a. Megasporogenesis – formation of
female gametophyte
b. Microsporogenesis – formation of male
gametophyte
Sporogenesis – involves a reduction
division process that produces haploid
gametes: egg in embyo sac and sperm
in the pollen grain

20. b. Pollination – transfer of the pollen grain
from the anther to a stigma of a flower
a. Self-pollination – pollen is transferred
from the anther to the stigma of the
same flower
b. Cross-pollination – pollen is transferred
from the anther to the stigma of another
plant

21. c. Double-fertilization
Pollen grain with two nuclei (generative and tube
nucleus)
generative nucleus  moves into the pollen tube
and forms two sperm nuclei
tube nucleus  grows through the stigma, style
and into the ovule, clearing the way for the
entry of sperm nuclei
1 sperm nuclei (N) + 1 egg (N) = zygote (2N)
1 sperm nuclei (N) + 2 polar nuclei = endosperm
(3N)

22. d. Fruit and seed development
ovary  fruit
ovule  seed
Seed  embryo, stored food and seed coat/testa
Embryo  cotyledon, hypocotyl and epicotyl

23. e. Seed Germination
Viability – ability of the seed to germinate
Conditions:
a. Suitable temperature ( between 16C and 27 
C)
b. Plenty of moisture
c. Sufficient oxygen
Seedling  young plant that develops out of a plant
embryo from a seed
radicle – root
hypocotyl – shoot
cotyledons – seed leaves