Genetic Diversity

Question 1

What are differences in species due to?

Answer 1

• result of differences in the genes the organisms possess

Question 2

What are differences within species due to?

Answer 2

• all members of the same species have the same genes so the differences between these individuals is a result of the difference in the combinations of alleles they possess

Question 3

What is genetic diversity?

Answer 3

• total number of different alleles within a population

Question 4

What causes genetic diversity?

Answer 4

1. Mutations
   - produce new alleles of genes to increase variation
2. Meiosis
   - crossing over
   - independent segregation
   - random fertilisation of ovum by sperm

Question 5

How does genetic diversity increase chances of survival?

Answer 5

• greater the genetic diversity, more likely that some individuals in a population will be able to survive an environmental change
• they will possess a characteristic that suits the new environmental conditions and are able to survive the change

Question 6

What is allele frequency?

Answer 6

• the number of times an allele appears in a gene pool

Question 7

What is a gene pool?

Answer 7

• the total number of alleles in a particular population in a specific time

Question 8

What are most characteristics influenced by?

Answer 8

• more than one gene (poly gene)
• more influenced by the environment than ones determined by a single gene
• the effect of environment on polygenes produce individuals in populations that vary about the mean

Question 9

Model answer on natural selection

Answer 9

1. Within any population of a species there will be a gene pool containing a wide variety of alleles
2. Random mutations of alleles within this gene pool may result in new alleles of a gene, which in most cases will be harmful
3. However, in new environments, the new allele might give its possessor an advantage over other individuals in the population
4. Will be better adapted and more likely to survive
5. More likely to obtain resources and so grow more rapidly and survive longer
6. Have a better chance of breeding successfully and producing more offspring
7. Can pass on alleles to next generation
8. Therefore, it is the new allele that gave the parents a survival advantage in competition for survival
9. Over many generations, the number of individuals with the new ‘advantageous’ allele will increase at the expense of the individuals with ‘less advantageous’ alleles
10. Over time, the frequency of the new ‘advantageous’ allele increases while that of the ‘less advantageous’ allele decreases