Topic 3 - GENETICS
- Created by: Aamna.M
- Created on: 14-05-17 12:13
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3.1b - asexual reproduction
Advantages
- Asexual reproduction can produce lots of offspring very fast can produce offspring very quickly because the reproductive cycle (the time it takes to produce independant offspring) is so fast.
- This can allow organisms to colonise a new area rapidly - large colonies can out compete other organisms for resources
- Only one parent is needed - this means that organisms can reproduce whenever conditions are favourable, without having to wait for a mate
- Therefore they can also conserve resources as they don't need to find a partner.
Disadvantages
- There is no genetic variation between offspring in the population - vunerable to disease
- So, if the environment changes and conditions become unfavourable, the whole population may be affected
- Unfavourable mutations are passed on to future generations
- No competiton for breeding so increased competition for resources as population booms
3.2b - sexual reproduction
Advantages
- sexual reproduction creates genetic variation within the population, which means that different individuals have different characteristics.
- This means that if the environmental conditions change, it's more likely that some individuals in the population will have the characteristics to survive the change
- This can lead to natural selection and evolution as species become better adapted to their new environment
Disadvantages
- It takes more time and energy than as.rep. so offpring produce fewer offspring in their lifetime
- Two parents are needed for sexual reproduction. This can be a problem if the individuals are isolated.
3.3b - The role of Meiosis
- ONLY takes place in the reproductive organs.
- Cells divide here to make gametes.
- The gametes only contain one chromosome from each pair (haploid).
- One gamete from each of your parents fuses to make a zygote.
- It doesn't produce identical cells
DIVISION 1
- Before division the cell duplicates it's DNA.
- The chromosomes line up in pairs in the centre of the cell; one came from…
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