Question: Sexual Reproduction leads to greater variation within a species. Identify the two sources of variation that occurs within meiosis ans explain what they are and how they lead to a greater number of genetic variance within offspring. 6 MARKS
This was my answer which received 4/6. I lost a mark on each of the explanation/definition of what they are but the teacher won't tell me why they were wrong. Any help would be greatly appreciated.
Answer:
The two sources of variation that occur within meiosis are: 1) Crossing Over 2) Random segregation
Crossing Over
This is the process in which homologous chromosomes exchange segment of genes with eachother, leading to a resultant which has a different order of genes to the ones of the parent. This leads to a greater number of variation within offspring as the crossing over is random, meaning this mixing and matching will lead to unique chromosomes. This in turn leads to each member of species being variated from others.
Random Segregation
The alleles that undergoe meiosis randomly segregate, meaning that each haploid gamete has only one allele. This process is random and can lead to countless possibilities of which has what allele. Hence, this increases the genetic variations within offspring as males and females carry numerous gametes which are all different from eachother, so in reproduction when the gametes make the zygote, the possibilities of offspring are numerous.
This was my answer which received 4/6. I lost a mark on each of the explanation/definition of what they are but the teacher won't tell me why they were wrong. Any help would be greatly appreciated.
Answer:
The two sources of variation that occur within meiosis are: 1) Crossing Over 2) Random segregation
Crossing Over
This is the process in which homologous chromosomes exchange segment of genes with eachother, leading to a resultant which has a different order of genes to the ones of the parent. This leads to a greater number of variation within offspring as the crossing over is random, meaning this mixing and matching will lead to unique chromosomes. This in turn leads to each member of species being variated from others.
Random Segregation
The alleles that undergoe meiosis randomly segregate, meaning that each haploid gamete has only one allele. This process is random and can lead to countless possibilities of which has what allele. Hence, this increases the genetic variations within offspring as males and females carry numerous gametes which are all different from eachother, so in reproduction when the gametes make the zygote, the possibilities of offspring are numerous.
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