B6 Asexual And Sexual Reproduction Flashcards
How do cells reproduce?
Asexually by mitosis
What is the result of asexually reproduction by mitosis in cells?
Two daughter cells, which are genetically identical to each other and to the parent cell.
What does sexual reproduction involve to form a zygote?
Involves meiosis and the production of genetically different gamers, which fuse together to form a zygote at fertilisation.
What is the advantage of asexual reproduction?
Can produce lots of offspring very quickly, because the reproductive cycle is so fast.
This can allow organisms to colonise a new area rapidly.
(Example, E. coli bacteria can divide every 20 minutes in the lab)
Why is one parent an advantage in asexual reproduction?
Means organisms can reproduce whenever conditions are favourable without having to wait for a mate.
(Example, aphids reproduce asexually in the summer when there is plenty of food)
What are the advantages of sexual reproduction?
Creates a genetic variation within the population, which means different individuals have different characteristics
Why is it an advantage of sexual reproduction that it creates genetic variation?
If the environmental conditions change, it’s more likely that at least some individuals in the population will have the characteristics to survive the change.
Overtime this leads to evolution, as species become better adapted to their new environment.
Why is no genetic variation a disadvantage of asexual reproduction?
Al the individuals are genetically identical.
If the environment changes and conditions become unfavourable the whole population may be affected.
Give an example of how no genetic variation can be a disadvantage.
(Black Sigatoka)
Black Sigatoka is a disease that affects banana plants, which reproduce asexually.
So if there is an outbreak of the disease it is likely that all banana plants in the population will be affected as there are none that are resistant to it.
What are the disadvantages of sexually reproduction?
Take more time and energy
Produce fewer offspring
Two parents needed
Why is time and energy used for sexual reproduction a disadvantage?
Organisms need to find and attract mates, which takes time and energy.
(Example male bowerbirds build structures out of twigs and then dance to impress females)
Fewer offspring are produced.
Why is two parents a disadvantage of sexual reproduction?
This can be a problem if individuals are isolated.
Example polar bears often live alone, so male polar bears may have to walk up to 100 miles to find a mate
Strawberry plants can reproduce asexually. Explain one disadvantage of this form of reproduction (2 marks)
Asexual reproduction produces genetically identical organisms (1 mark)
This means that if environmental conditions change, making it difficult for the strawberry plant to survive, the whole population of strawberry plants could be affected (1 mark)
