Transcript asexual reproduction

The process of making new individuals (offspring) from existing
individuals (parents).
ASEXUAL REPRODUCTION:
 Asexual reproduction is reproduction without gametes.
 Gametes are the male and female sex cells.
Eg. male = sperm, female = egg.
 The offspring produced by asexual reproduction are often
identical to their parents.
 Asexual reproduction allows for large number of offspring
to be produced rapidly.
 Only one ‘parent’ is needed for asexual reproduction.
Examples of Asexual
Reproduction in plants:
•RHIZOMES- horizontal stems that
grow under the surface of the ground.
Eg. ferns.
•SPORES – reproductive cells with a
protective coat, develop into new
individuals it they land in a favourable
location. Eg. fungi and ferns.
•SUCKERS – new plants grow form the
roots of parent plant, eg. blackberry.
•VEGETATIVE PROPAGATION –
Runners or horizontal stems, eg. grass
species and strawberry plants.
•CUTTINGS – sections of shoots that
have broken off the parent plant can
grow new roots.
Figure 1: Potato plant
Figure 1: Asexual Reproduction in
Plants- Strawberry Plant runners
Asexual Reproduction in
Animals:
 FISSION (Binary fission)- similar to cellular
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division where one organism splits into
two. Eg. Bacteria and protozoa
BUDDING- new individual grows as a bud
on the side of the parent organism’s body.
Eg. Hydra and corals
REGENERATION/ FRAGMENTATIONParent “breaks” into two or more pieces,
each of which grows into a new individual.
Eg. flat-worms and some starfish.
SPLITTING IN HALF- After the nucleus
reproduces amoebas split into two similar
sized halves that grow into new individuals.
PARTHENOGENISIS- young are produced
from unfertilised eggs. Eg. Aphids,
honeybees and whiptail lizards. Babies are
identical to the mother.
Figure 2: Asexual reproduction in animals
SEXUAL REPRODUCTION
 Sexual reproduction requires the joining of both male and female
gametes in a process called FERTILISATION.
 The offspring produced by sexual reproduction are not identical to the
parents.
 Results in greater variety of offspring than asexual reproduction.favoured if environment is changing because it results in greater
genetic variation.
 Cell produced when the sperm and the egg fuse (fertilisation) is called
the zygote.
ASEXUAL REPRODUCTION
REPRODUCTION
SEXUAL
Parent cell or organism
Some genetic
material
passed on
MEIOSIS
Genetic information is passed on
Sperm cell
Egg cell
MITOSIS
Zygote
MITOSIS
Offspring genetically identical to parent
Offspring not
genetically identical
to parents
COMPARISON OF ASEXUAL AND SEXUAL
REPRODUCTION
Asexual Reproduction
Sexual reproduction
 One parent involved.
 Two parents usually involved.
 Offspring are genetically
 Offspring contain genetic
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identical to parent.
Involves mitosis.
No fertilisation required.
Many offspring are produced in
a short time.
Survival rate is good if offspring
live in same environment as
parent.
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material from both parents
Involves meiosis.
Fertilisation required.
Number of offspring produced
at one time is small.
Greater genetic variation
provides some offspring with a
better chance to survive, if the
environment changes.