Asexual and sexual plant reproduction:
Asexual Sexual
Characteristics: ● Genetically identical to the parent ❖ Fusion of gametes (pollen and ovules)
● Formed by mitosis ❖ Requires two parents
● Offspring are clones
Advantages: ● Can increase population size quickly (energy not ❖ Genetic variability
wasted on looking for a mate) – more likely to survive
● Shortened reproduction time allows for plants to – varied population allows for some plants to be
crowd out competition from other plants better adapted to the environment eg: drought
● Genetically identical – favourable traits continue resistant .: allowing higher crop yield of seeds and
● Grafting allows new varieties through different fruit than parent plants
parents ❖ Farmers can cross-pollinate to pass on favourable
● Tissue cultures allow virus-free mother stock characteristics from one crop to another to produce
● Propagation can take place year-round – avoids better seeds and fruit
seed dormancy
Disadvantages: ● Genetically identical (no variation) ❖ Variation might allow the expression of a mutation
1. causes weaknesses in parents always to be or recessive gene in the genetic makeup of the
transmitted (all susceptible to the same offspring
diseases) ❖ Takes longer than asexual – seed germination
2. If an environmental change occurred the ❖ Uses more energy – gamete formation
whole population would be at ❖ It can require external agents – pollinators, wind
● No genetic variation ❖ Requires two parents
● Genetic weaknesses can’t be bred out
● All are vulnerable to the same diseases
● More difficult to store organs of asexual
reproduction eg: tubers instead of seeds
Similarities: Results in new life Results in new life
Differences: ● Genetically identical ❖ Genetically varied
● Requires one parent ❖ Requires 2 parents
● It does not require external agents ❖ Can require external agents
, Types of pollination:
Cross-pollination: Self-pollination:
Advantages ● Useful characteristics can be produced ● The plant doesn't have to rely on pollinators.
● Undesirable characteristics can be eliminated
● Increase adaptability – genetic variability ● It eliminates a lot of unwanted recessive
● Produces larger seeds – hybrid vigour characteristics.
● Seed production never falls below average
minimum
Disadvantages ➔ Depends on external organisms – pollinators ➔ Prevents genetic variability
➔ Less economical
– uses large amounts of energy ❖ Avoided as much as possible, to avoid:
–produces more pollen grains than possibly – stigmas are above the anthers to make it more
needed difficult for pollen to reach
➔ Favourable characteristics could be lost as they – pollen will ripen on the flower at different times
could be recessive to egg cells
➔ Unfavourable characteristics could remain
Asexual Sexual
Characteristics: ● Genetically identical to the parent ❖ Fusion of gametes (pollen and ovules)
● Formed by mitosis ❖ Requires two parents
● Offspring are clones
Advantages: ● Can increase population size quickly (energy not ❖ Genetic variability
wasted on looking for a mate) – more likely to survive
● Shortened reproduction time allows for plants to – varied population allows for some plants to be
crowd out competition from other plants better adapted to the environment eg: drought
● Genetically identical – favourable traits continue resistant .: allowing higher crop yield of seeds and
● Grafting allows new varieties through different fruit than parent plants
parents ❖ Farmers can cross-pollinate to pass on favourable
● Tissue cultures allow virus-free mother stock characteristics from one crop to another to produce
● Propagation can take place year-round – avoids better seeds and fruit
seed dormancy
Disadvantages: ● Genetically identical (no variation) ❖ Variation might allow the expression of a mutation
1. causes weaknesses in parents always to be or recessive gene in the genetic makeup of the
transmitted (all susceptible to the same offspring
diseases) ❖ Takes longer than asexual – seed germination
2. If an environmental change occurred the ❖ Uses more energy – gamete formation
whole population would be at ❖ It can require external agents – pollinators, wind
● No genetic variation ❖ Requires two parents
● Genetic weaknesses can’t be bred out
● All are vulnerable to the same diseases
● More difficult to store organs of asexual
reproduction eg: tubers instead of seeds
Similarities: Results in new life Results in new life
Differences: ● Genetically identical ❖ Genetically varied
● Requires one parent ❖ Requires 2 parents
● It does not require external agents ❖ Can require external agents
, Types of pollination:
Cross-pollination: Self-pollination:
Advantages ● Useful characteristics can be produced ● The plant doesn't have to rely on pollinators.
● Undesirable characteristics can be eliminated
● Increase adaptability – genetic variability ● It eliminates a lot of unwanted recessive
● Produces larger seeds – hybrid vigour characteristics.
● Seed production never falls below average
minimum
Disadvantages ➔ Depends on external organisms – pollinators ➔ Prevents genetic variability
➔ Less economical
– uses large amounts of energy ❖ Avoided as much as possible, to avoid:
–produces more pollen grains than possibly – stigmas are above the anthers to make it more
needed difficult for pollen to reach
➔ Favourable characteristics could be lost as they – pollen will ripen on the flower at different times
could be recessive to egg cells
➔ Unfavourable characteristics could remain
