Slides in this set

Slide 1

Slide 2

Preview of page 2

What are clones:
·Genes cells or whole organisms that carry the same
genetic material
Examples of clones:
·Identical twins produced when a zygote splits in two are
natural clones
·When plants reproduce asexually producing runners
the plants are clones
·When bacteria reproduce asexually by binary fission
the resulting bacteria are clones of the original
The production of clones DNA cells and organisms is a
natural process for growth and reproduction that can
also be achieved through artificial means…read more

Slide 3

Preview of page 3

Advantages of asexual reproduction:
·It's quick, allows organisms to reproduce rapidly and take
advantage of resources in the environment
·Can be completed if sexual reproduction fails or is not
·All offspring have the same genetic information to enable
them to survive in their environment
Disadvantages of asexual reproduction:
·No genetic variety is produced so any genetic parental
weakness will be in the offspring
·If the environment changes then all genetically identical
organisms would suffer…read more

Slide 4

Preview of page 4

Natural vegetative propagation in plants:
In plants a number of species (such as the English elm) are
adapted to reproduce asexually if there is damage to the parent
plant, this allows the species to survive catastrophe such as
disease or burning.
New growth in the form of two root suckers (basal sprouts)
appears in two months of destruction of the main trunk, these
suckers grow from the meristem tissue in the trunk close to the
ground where the least damage is likely to have occurred.
Advantages to the elm of vegetative propagation:
·Help the elm to spread as they can grow all around the trunk,
the suckers grow into a circle of new elms called a clonal patch
·The clonal patch puts out new suckers so the patch expands as
far as the resources permit
Disadvantages to the elm of vegetative propagation:
·There is no genetic variation within the cloned population so
natural selection can't occur, so for example when the Dutch elm
disease spread through Europe's elms the English elms all
responded by growing root suckers but as the new elms were
clones of the old one they don't have any resistance to the
disease so remain just as vulnerable.…read more

Slide 5

Preview of page 5

Artificial vegetative propagation: There are two main
methods to this
1) Taking cuttings:
The cut end of the
The cutting forms a
a section of the stem is stem is treated with
new plant which is a
cut between leaf joints plant hormones to
clone of the original
(nodes) encourage root growth
parent plant
and planted
2) Grafting:
A shoot section of a woody
The graft grows and is
plant (usually a fruit tree or
genetically identical to the
rosebush) is joined to an
parent plant but the rootstock
already growing root and stem
is genetically different
(a rootstock)…read more

Slide 6

Preview of page 6

Micro propagation by callus tissue culture:
After another few
After a few weeks weeks the
single callus cells growing shoots The growing
a small piece of
Cells in the tissue can be removed are transferred plants are
tissue is taken
The explant is divide forming a from the mass onto s different transferred to a
from the plant to
placed on a mass of and placed on a growing medium greenhouse to be
be cloned usually
nutrient growth undifferentiated growth medium containing acclimatised and
from the shoot
medium cells called a containing plant different grown further
tip this is called
callus hormones that hormone before being
an explant
encourage shoot concentrations planted outside
growth that encourage
root growth…read more

Slide 7

Preview of page 7
Preview of page 7

Slide 8

Preview of page 8
Preview of page 8

Slide 9

Preview of page 9
Preview of page 9

Slide 10

Preview of page 10
Preview of page 10


No comments have yet been made

Similar Biology resources:

See all Biology resources »