PLANT REPRODUCTION
ADVANTAGES AND DISADVANTAGES
ASEXUAL REPRODUCTION
Advantages Disadvantages
All individuals can produce Unless, there is a mutation, there
offspring: is no genetic variation in the
No expenditure of energy to produce offspring:
gametes or find a mate. No recombination of alleles. If the
environment changes the population
might be unable to adapt to the new
conditions and could die out.
The process is simple and fast: Overcrowding may occur:
Involves only mitosis(single bacterium Resources such as food might be in
dividing into two every 20 minutes) short supply.
It is very useful in
unchanging(stable) conditions:
If the parent is well-adapted to a
particular environment the genetically
identical offspring will also be well
adapted.
A favourable mutation can spread
rapidly:
Enabling the population to adapt
quickly to new environmental
conditions(resistance)
SEXUAL REPRODUCTION
Advantages Disadvantages
Results in variation which: There is high expenditure of
Is the basis of evolution energy as in plants special organs of
Gives organisms a better chance of reproduction need to be
survival in an unstable environment produced(flowers)
as the offspring may be able to adapt
to the new conditions.
May prevent the spread of disease as
the offspring may be unable to adapt
to the new conditions.
My reduce the chance of inheriting a
disease from a parent.
The reproduction process is much
slower than asexual reproduction:
takes time for the gamete production
and the meeting of gametes.
Unfavourable mutations and
recessive genes might be expressed
in the offspring.
Outside agents may be needed in
plants to carry pollen or seeds.
, HOW DOES SEXUAL REPRODUCTION TAKE PLACE:
Sexual reproduction is far more complicated than asexual
- Gametogenesis:
The diploid parent produces gametes(sex cells) in the gonads(sex
organs) by meiosis.
The gametes are haploid: contain half the number of chromosomes.
- Mating(animal) or pollination(plant):
The male and female gametes are brought together
- Fertilization:
Fusion of 2 haploid cells/gametes(sperm and egg cell) to form a
diploid zygote.
The new zygote is diploid: two sets of chromosomes
Zygote grows by mitotic division into a new individual.
GAMETES:
- Female gamete is quite large and not
motile while the male gamete is small and
motile in animals.
- In animals, the male gamete is known as
the sperm and the female, egg/ovum
- In many plants, the male gamete is just a
nucleus in a pollen grain while the female
gamete I an egg in an embryo sac.
ANGIOSPERM REPRODUCTION:
Angiosperm:
- Plants with flowers which produce ovules enclosed in an
ovary, not naked on a cone scale(like gymnosperms: pines).
- Grow in almost every habitat, except the open ocean(where algae
are found).
What is a flower?
- The organ of sexual reproduction as it contains the reproductive
organs and often will attract pollinators.
- Many flowers make both male and female gametes:
hermaphrodite(bisexual)
- The male gametes are found inside the pollen grains which re
produced by the anthers.
- The female gametes are inside the ovules which are found enclosed
by the ovary.
ADVANTAGES AND DISADVANTAGES
ASEXUAL REPRODUCTION
Advantages Disadvantages
All individuals can produce Unless, there is a mutation, there
offspring: is no genetic variation in the
No expenditure of energy to produce offspring:
gametes or find a mate. No recombination of alleles. If the
environment changes the population
might be unable to adapt to the new
conditions and could die out.
The process is simple and fast: Overcrowding may occur:
Involves only mitosis(single bacterium Resources such as food might be in
dividing into two every 20 minutes) short supply.
It is very useful in
unchanging(stable) conditions:
If the parent is well-adapted to a
particular environment the genetically
identical offspring will also be well
adapted.
A favourable mutation can spread
rapidly:
Enabling the population to adapt
quickly to new environmental
conditions(resistance)
SEXUAL REPRODUCTION
Advantages Disadvantages
Results in variation which: There is high expenditure of
Is the basis of evolution energy as in plants special organs of
Gives organisms a better chance of reproduction need to be
survival in an unstable environment produced(flowers)
as the offspring may be able to adapt
to the new conditions.
May prevent the spread of disease as
the offspring may be unable to adapt
to the new conditions.
My reduce the chance of inheriting a
disease from a parent.
The reproduction process is much
slower than asexual reproduction:
takes time for the gamete production
and the meeting of gametes.
Unfavourable mutations and
recessive genes might be expressed
in the offspring.
Outside agents may be needed in
plants to carry pollen or seeds.
, HOW DOES SEXUAL REPRODUCTION TAKE PLACE:
Sexual reproduction is far more complicated than asexual
- Gametogenesis:
The diploid parent produces gametes(sex cells) in the gonads(sex
organs) by meiosis.
The gametes are haploid: contain half the number of chromosomes.
- Mating(animal) or pollination(plant):
The male and female gametes are brought together
- Fertilization:
Fusion of 2 haploid cells/gametes(sperm and egg cell) to form a
diploid zygote.
The new zygote is diploid: two sets of chromosomes
Zygote grows by mitotic division into a new individual.
GAMETES:
- Female gamete is quite large and not
motile while the male gamete is small and
motile in animals.
- In animals, the male gamete is known as
the sperm and the female, egg/ovum
- In many plants, the male gamete is just a
nucleus in a pollen grain while the female
gamete I an egg in an embryo sac.
ANGIOSPERM REPRODUCTION:
Angiosperm:
- Plants with flowers which produce ovules enclosed in an
ovary, not naked on a cone scale(like gymnosperms: pines).
- Grow in almost every habitat, except the open ocean(where algae
are found).
What is a flower?
- The organ of sexual reproduction as it contains the reproductive
organs and often will attract pollinators.
- Many flowers make both male and female gametes:
hermaphrodite(bisexual)
- The male gametes are found inside the pollen grains which re
produced by the anthers.
- The female gametes are inside the ovules which are found enclosed
by the ovary.
