2. Asexual reproduction
Formation of a new individual from a single
parent without fusion of an egg and a sperm
No specialized sex cells involved
Offspring is genetically identical to the
parent
12. Runners
Beach strawberry
Horizontal stems spread out over the surface of the sand.
If a node of a runner touches the soil, it will sprout roots
and develop into a complete plant.
18. Advantages of vegetative propagation
1. The offspring is usually genetically identical to
the parent
2. The plants do not depend on other agents of
pollination
3. The production of new individual is fast &
plentiful
4. The new individuals are able to obtain enough
nutrients for early development from the
parent plants
19. Disadvantages of Vegetative Propagation
1. No variation in the new offspring. If the
environment changes, the offspring has less
ability to adapt to the new environment.
2. Dispersal of new offspring is limited. It will
cause congestion & competition.
20. Fragmentation & Regeneration
• Fragmentation -
extreme form of
regeneration
• Each fragment will
develop into a new
individual
• Eg. Planaria (free-living
flatworm)
22. • Many invertebrates can replace lost or injured
body parts
• lizard - tail
• earthworm can regrow its head
• starfish – arms
• crab – legs, pincers
28. Budding
• An outgrowth (bud)
from a parent cell, later
detached from the
parent & is released as
an independent
individual
• Eg Cnidarian like
Hydra, Obelia,
Saccharomyces (yeast)
29. Yeast cell reproduces by budding which is like binary fission
except that the two cells produced are of unequal sizes
30.
31.
32.
Developmental process of an egg into a new
individual without having been fertilized
2 kinds
1. Haploid Parthenogenesis
eg honeybee (Apis)
2. Diploid Parthenogenesis
eg aphid (Aphis)
Parthenogenesis
33.
34. Haploid Parthenogenesis
• Haploid egg cells are produced in the ovaries by
meiosis
• The egg cells then divide, develop into adults
without having been fertilized, forming a
specific caste of social insects.
• eg insects like Hymenophtera - ant, wasp,
honey bee
36. Diploid Parthenogenesis
• Diploid ovum is formed during meiosis as
a result of the non-disjunction of
chromosomes
• The diploid egg then develops into a
diploid female eg. aphids
39. Binary Fission
• Involves replication of the cell’s DNA, division
of the nucleus and cytoplasm
• Cells divide into two
• The new individuals are genetically identical to
the parent
• Limited to unicellular organism
• eg bacteria, Amoeba, Paramecium
43. Sporulation
OEg Dryopteris, Plasmodium
O Involves asexual spores produced by mitosis
or meiosis in a parent cell
OSpores – dormant, have a protective outer
coat, enable them to resist adverse
environmental conditions
OAsexual spores – abundant, small, light, with
minimal food stores
OAsexual spores - in fungi & Filicinophyta,
produced in sporangia
46. Polyembryony
• Production of two or more embryos by the division of
one zygote.
• examples
1. The division of human zygote into two embryos that
develop into identical twins.
2. The division of one zygote into many embryos in
nematode like Fasciola.
47. Paedogenesis
• A type of asexual reproduction of the larva,
pupa or premature form of an organism
Paedogenesis in larva
Eg. Amphioxus larva
Eggs are produced by the female larva
Female larva may develop into mature
organisms or may remain
at the larva stage
Male larva will develop
into adult male
