Topic 3 (Sexual And Asexual Reproduction)

Question 1

How does meiosis happen?

Answer 1

Before division, cell duplicates DNA and the chromosomes, in the first division the chromosomes lineup in pairs in the centre of the cell then the pairs are pulled apart so that each new cell has a copy of chromosome, each new cell will have a mixture of the mothers and father chromosomes which creates genetic variation in offspring. in the second division, the chromosomes lineup in the middle and a pull apart, four genetically different cells that are haploid are made.

Question 2

When the sexual reproduction used?

Answer 2

Is used by haploid gametes which fuse together for fertilisation to take place

Question 3

Advantages of asexual reproduction

Answer 3

Can produce lots of offspring very quickly because the reproductive cycle is so fast. For example, bacteria such as E.coli can divide every half an hour. This can allow organisms to colonise a new rapidly.

Only one parent is needed, which means that they can produce whenever conditions are favourable without having to find a mate

Question 4

Disadvantages of a social reproduction

Answer 4

There is no genitive variation between the offsprings in the population so if the environment changes and the conditions become unfavourable, the population may be affected.
For example, black Sigatoka is a disease that affects banana plants which reproduces asexually so if there’s an outbreak of the disease it’s likely that all banana plants in the population will be affected as there are none resistant to it.

Question 5

Advantages of sexual reproduction

Answer 5

Sexual reproduction creation variation within the population, which means they have different characteristics. This means if the environmental conditions changes it’s more likely that at least some individuals will have the characteristics to survive. Overtime, can lead to natural selection and evolution as the speech will become better than environment

Question 6

Disadvantages of sexual reproduction

Answer 6

It takes more time and energy so fewer offsprings are produced in the organisms lifetime. As organisms need to find and attract mates which takes time and energy.
Two parents are needed for sex reproduction which can be a problem if individuals are isolated, e.g. polar bears often live alone.