TOPICS Advantages and disadvantages of asexual reproduction
Advantages and disadvantages of sexual reproduction Advantages and
disadvantages of asexual reproduction Advantages and disadvantages
of sexual reproduction
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PLANT REPRODUCTION Is the ability of living organisms to
produce a new generation of themselves Important for survival and
evolution of a species Is the ability of living organisms to
produce a new generation of themselves Important for survival and
evolution of a species
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TYPES OF REPRODUCTION
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ASEXUAL REPRODUCTION Also called vegetative propagation
Production of a new generation of the same species by one parent
Takes place by mitosis All new organisms are genetically identical
to their parents and to each other Such organisms are called
clones
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VEGETATIVE REPRODUCTION STEMS
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STOLON Long thin stems that go across the ground
Chlorophytum
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VEGETATIVE REPRODUCTION STEMS
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VEGETATIVE REPRODUCTION STEMS
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VEGETATIVE REPRODUCTION
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ROOTS Suckers develop from Roots and grow into new plants
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VEGETATIVE REPRODUCTION Root tubers are swollen roots E.g.
dahlia ROOTS
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VEGETATIVE REPRODUCTION New plants can develop directly from
leaves Eg Streptocarpus spp. LEAVES Streptocarpus leaf
cuttings
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ARTIFICIAL VEGETATIVE REPRODUCTION
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ADVANTAGES OF ASEXUAL REPRODUCTION Only one parent needed and
all individuals can produce offspring No special organs of
reproduction are required (eg flowers) The process is simple and
fast only mitosis involved No outside agents such as pollinators
are needed Little energy is used (do not have to produce
reproductive organs) Only one parent needed and all individuals can
produce offspring No special organs of reproduction are required
(eg flowers) The process is simple and fast only mitosis involved
No outside agents such as pollinators are needed Little energy is
used (do not have to produce reproductive organs)
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ADVANTAGES OF ASEXUAL REPRODUCTION New plants are genetically
identical No variation Successful varieties are maintained Will be
the same year after year good for commercial crops Eg potatoes and
strawberries New plants are genetically identical No variation
Successful varieties are maintained Will be the same year after
year good for commercial crops Eg potatoes and strawberries
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ADVANTAGES OF ASEXUAL REPRODUCTION Asexual reproduction is
useful in stable conditions If the parent is well adapted to a
particular environment the offspring also will be A favourable
mutation can spread rapidly, enabling a population to adapt quickly
to any new environmental conditions Asexual reproduction is useful
in stable conditions If the parent is well adapted to a particular
environment the offspring also will be A favourable mutation can
spread rapidly, enabling a population to adapt quickly to any new
environmental conditions Mutation = change in a chromosome
resulting in a new characteristic
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ADVANTAGES OF ASEXUAL REPRODUCTION By avoiding seed dormancy,
plants can be propogated throughout the year independent of
seasonal changes Germination after seed dormancy Germination
dormancy
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DISADVANTAGES OF ASEXUAL REPRODUCTION No variation no chance of
improving the quality of the species Overcrowding may occur and
resources such as food might be in short supply Genetic weaknesses
cannot be bred out Infectious diseases (caused by viruses) are
likely to be passed on to the new crop No variation no chance of
improving the quality of the species Overcrowding may occur and
resources such as food might be in short supply Genetic weaknesses
cannot be bred out Infectious diseases (caused by viruses) are
likely to be passed on to the new crop Overcrowded basil No
variation
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SEXUAL REPRODUCTION IN PLANTS Is the production of a new
generation by bringing together the genetic material of two parents
The offspring will therefore be genetically different from the
parents
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PROCESS OF SEXUAL REPRODUCTION IN PLANTS Diagram Parents
produce gametes in sex organs Male and femae gametes are brought
close together by pollination Male and female gametes fuse
(fertilisation) Zygote grows into a new plant
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ADVANTAGES OF SEXUAL REPRODUCTION Results in variation which:
Is the basis of evolution Gives organisms a better chance of
survival in an unstable environment as the offspring may be able to
adapt to the new conditions May prevent the spread of disease as
the offspring might be genetically resistant to a particular
disease Can result in the quick elimination of harmful mutations
Results in variation which: Is the basis of evolution Gives
organisms a better chance of survival in an unstable environment as
the offspring may be able to adapt to the new conditions May
prevent the spread of disease as the offspring might be genetically
resistant to a particular disease Can result in the quick
elimination of harmful mutations Mutation = change in a chromosome
resulting in a new characteristic
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ADVANTAGES OF SEXUAL REPRODUCTION Seeds are usually dispersed
widely which gives them more space and nutrients
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Drosera cistiflora is a plant with a wide range of floral
colour variations and many of these can be observed in fynbos and
renosterveld habitats during spring. Flowers vary in size and
colour.
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DISVANTAGES OF SEXUAL REPRODUCTION There is a high expenditure
of energy In plants special organs of reproduction need to be
produced e.g. flowers The reproduction process is slow Unfavourable
mutations and recessive genes might be passed on to the offspring
Outside agents might be needed in plants to carry pollen or seeds
There is a high expenditure of energy In plants special organs of
reproduction need to be produced e.g. flowers The reproduction
process is slow Unfavourable mutations and recessive genes might be
passed on to the offspring Outside agents might be needed in plants
to carry pollen or seeds
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CHARACTERISTICSASEXUAL REPRODUCTION SEXUAL REPRODUCTION Number
of parentsOneTwo Reproductive organsLeaves, roots and stemsflowers
Rate of processFaster (no gamete formation or pollination) Slower
(gamete formation or pollination) Outside agentsNone neededOutside
pollinators often need Energy inputlowHigh energy is needed to make
flowers Ability to adapt to environment No if environment changes,
organisms die Yes offspring adapt to the changing environment and
survive Possibility of evoultionLow no genetic variation Good
genetic variation When is the method an advantage In a stable
environmentIn an unstable environment organisms can adapt HOW DO
ASEXUAL AND SEXUAL REPRODUCTION COMPARE
